diff --git a/core/core.services.yml b/core/core.services.yml
index f371585..4c0553f 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -137,10 +137,10 @@ services:
     factory_class: Drupal\Component\Utility\Settings
     factory_method: getSingleton
   state:
-    class: Drupal\Core\KeyValueStore\KeyValueStoreInterface
-    factory_method: get
-    factory_service: keyvalue
-    arguments: [state]
+    class: Drupal\Core\KeyValueStore\State
+    arguments: ['@keyvalue']
+    tags:
+      - { name: persist }
   queue:
     class: Drupal\Core\Queue\QueueFactory
     arguments: ['@settings']
diff --git a/core/includes/common.inc b/core/includes/common.inc
index fc46b9b..138c11a 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -399,15 +399,14 @@ function drupal_add_feed($url = NULL, $title = '') {
   if (isset($url)) {
     $stored_feed_links[$url] = theme('feed_icon', array('url' => $url, 'title' => $title));
 
-    $build['#attached']['drupal_add_html_head_link'][][] = array(
+    drupal_add_html_head_link(array(
       'rel' => 'alternate',
       'type' => 'application/rss+xml',
       'title' => $title,
       // Force the URL to be absolute, for consistency with other <link> tags
       // output by Drupal.
       'href' => url($url, array('absolute' => TRUE)),
-    );
-    drupal_render($build);
+    ));
   }
   return $stored_feed_links;
 }
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index 36b6b14..e0fa799 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -453,10 +453,8 @@ function install_begin_request(&$install_state) {
     $settings['keyvalue_default'] = 'keyvalue.memory';
     new Settings($settings);
 
-    $container->register('state', 'Drupal\Core\KeyValueStore\KeyValueStoreInterface')
-      ->setFactoryService(new Reference('keyvalue'))
-      ->setFactoryMethod('get')
-      ->addArgument('state');
+    $container->register('state', 'Drupal\Core\KeyValueStore\State')
+      ->addArgument(new Reference('keyvalue'));
 
     // Register Twig template engine for use during install.
     CoreServiceProvider::registerTwig($container);
diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 98be6de..e6326d8 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1268,14 +1268,8 @@ function template_preprocess_status_messages(&$variables) {
  *     is used as its CSS class. Each link should be itself an array, with the
  *     following elements:
  *     - title: The link text.
- *     - route_name: (optional) The name of the route to link to. If omitted
- *       (and if 'href' is omitted as well), the 'title' is shown as
- *       a plain text item in the links list.
- *     - route_parameters: (optional) An array of route parameters for the link.
- *     - href: (optional) The link URL. It is preferred to use 'route_name' and
- *       'route parameters' for internal links. Use 'href' for links to external
- *       URLs. If omitted (and if 'route_name' is omitted as well), the 'title'
- *       is shown as a plain text item in the links list.
+ *     - href: The link URL. If omitted, the 'title' is shown as a plain text
+ *       item in the links list.
  *     - html: (optional) Whether or not 'title' is HTML. If set, the title
  *       will not be passed through
  *       \Drupal\Component\Utility\String::checkPlain().
@@ -2221,12 +2215,7 @@ function template_preprocess_html(&$variables) {
   if (theme_get_setting('features.favicon')) {
     $favicon = theme_get_setting('favicon.url');
     $type = theme_get_setting('favicon.mimetype');
-    $build['#attached']['drupal_add_html_head_link'][][] = array(
-      'rel' => 'shortcut icon',
-      'href' => Url::stripDangerousProtocols($favicon),
-      'type' => $type,
-    );
-    drupal_render($build);
+    drupal_add_html_head_link(array('rel' => 'shortcut icon', 'href' => Url::stripDangerousProtocols($favicon), 'type' => $type));
   }
 
   $site_config = \Drupal::config('system.site');
@@ -2509,12 +2498,7 @@ function template_preprocess_maintenance_page(&$variables) {
   if (theme_get_setting('features.favicon')) {
     $favicon = theme_get_setting('favicon.url');
     $type = theme_get_setting('favicon.mimetype');
-    $build['#attached']['drupal_add_html_head_link'][][] = array(
-      'rel' => 'shortcut icon',
-      'href' => Url::stripDangerousProtocols($favicon),
-      'type' => $type,
-    );
-    drupal_render($build);
+    drupal_add_html_head_link(array('rel' => 'shortcut icon', 'href' => Url::stripDangerousProtocols($favicon), 'type' => $type));
   }
 
   // Get all region content set with drupal_add_region_content().
diff --git a/core/lib/Drupal.php b/core/lib/Drupal.php
index a03ee24..5441e30 100644
--- a/core/lib/Drupal.php
+++ b/core/lib/Drupal.php
@@ -288,7 +288,7 @@ public static function keyValue($collection) {
    * needs to be the same across development, production, etc. environments
    * (for example, the system maintenance message) should use \Drupal::config() instead.
    *
-   * @return \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @return \Drupal\Core\KeyValueStore\StateInterface
    */
   public static function state() {
     return static::$container->get('state');
diff --git a/core/lib/Drupal/Component/Plugin/PluginBag.php b/core/lib/Drupal/Component/Plugin/PluginBag.php
index 8ab051a..23d2d26 100644
--- a/core/lib/Drupal/Component/Plugin/PluginBag.php
+++ b/core/lib/Drupal/Component/Plugin/PluginBag.php
@@ -9,6 +9,9 @@
 
 /**
  * Defines an object which stores multiple plugin instances to lazy load them.
+ *
+ * The \ArrayAccess implementation is only for backwards compatibility, it is
+ * deprecated and should not be used by new code.
  */
 abstract class PluginBag implements \Iterator, \Countable {
 
@@ -27,7 +30,7 @@
   protected $instanceIDs = array();
 
   /**
-   * Initializes and stores a plugin.
+   * Initializes a plugin and stores the result in $this->pluginInstances.
    *
    * @param string $instance_id
    *   The ID of the plugin instance to initialize.
@@ -82,7 +85,7 @@ public function set($instance_id, $value) {
   /**
    * Removes an initialized plugin.
    *
-   * The plugin can still be used; it will be reinitialized.
+   * The plugin can still be used, it will be reinitialized.
    *
    * @param string $instance_id
    *   The ID of the plugin instance to remove.
@@ -92,7 +95,7 @@ public function remove($instance_id) {
   }
 
   /**
-   * Adds an instance ID to the available instance IDs.
+   * Adds an instance ID to the array of available instance IDs.
    *
    * @param string $id
    *   The ID of the plugin instance to add.
@@ -114,7 +117,7 @@ public function getInstanceIds() {
   }
 
   /**
-   * Sets all instance IDs.
+   * Sets the instance IDs property.
    *
    * @param array $instance_ids
    *   An associative array of instance IDs.
@@ -135,28 +138,28 @@ public function removeInstanceId($instance_id) {
   }
 
   /**
-   * {@inheritdoc}
+   * Implements \Iterator::current().
    */
   public function current() {
     return $this->get($this->key());
   }
 
   /**
-   * {@inheritdoc}
+   * Implements \Iterator::next().
    */
   public function next() {
     next($this->instanceIDs);
   }
 
   /**
-   * {@inheritdoc}
+   * Implements \Iterator::key().
    */
   public function key() {
     return key($this->instanceIDs);
   }
 
   /**
-   * {@inheritdoc}
+   * Implements \Iterator::valid().
    */
   public function valid() {
     $key = key($this->instanceIDs);
@@ -164,14 +167,14 @@ public function valid() {
   }
 
   /**
-   * {@inheritdoc}
+   * Implements \Iterator::rewind().
    */
   public function rewind() {
     reset($this->instanceIDs);
   }
 
   /**
-   * {@inheritdoc}
+   * Implements \Countable::count().
    */
   public function count() {
     return count($this->instanceIDs);
diff --git a/core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php b/core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php
index 5d43231..5bc4a7d 100644
--- a/core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php
+++ b/core/lib/Drupal/Core/Asset/CssCollectionOptimizer.php
@@ -8,6 +8,7 @@
 
 use Drupal\Core\Asset\AssetCollectionOptimizerInterface;
 use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 
 /**
  * Optimizes CSS assets.
@@ -38,7 +39,7 @@ class CssCollectionOptimizer implements AssetCollectionOptimizerInterface {
   /**
    * The state key/value store.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -51,10 +52,10 @@ class CssCollectionOptimizer implements AssetCollectionOptimizerInterface {
    *   The optimizer for a single CSS asset.
    * @param \Drupal\Core\Asset\AssetDumperInterface
    *   The dumper for optimized CSS assets.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @param \Drupal\Core\KeyValueStore\StateInterface
    *   The state key/value store.
    */
-  public function __construct(AssetCollectionGrouperInterface $grouper, AssetOptimizerInterface $optimizer, AssetDumperInterface $dumper, KeyValueStoreInterface $state) {
+  public function __construct(AssetCollectionGrouperInterface $grouper, AssetOptimizerInterface $optimizer, AssetDumperInterface $dumper, StateInterface $state) {
     $this->grouper = $grouper;
     $this->optimizer = $optimizer;
     $this->dumper = $dumper;
diff --git a/core/lib/Drupal/Core/Asset/CssCollectionRenderer.php b/core/lib/Drupal/Core/Asset/CssCollectionRenderer.php
index 09846c1..e1cb3cd 100644
--- a/core/lib/Drupal/Core/Asset/CssCollectionRenderer.php
+++ b/core/lib/Drupal/Core/Asset/CssCollectionRenderer.php
@@ -6,9 +6,8 @@
 
 namespace Drupal\Core\Asset;
 
-use Drupal\Core\Asset\AssetCollectionRendererInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
 use Drupal\Component\Utility\String;
+use Drupal\Core\KeyValueStore\StateInterface;
 
 /**
  * Renders CSS assets.
@@ -18,17 +17,17 @@ class CssCollectionRenderer implements AssetCollectionRendererInterface {
   /**
    * The state key/value store.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
   /**
    * Constructs a CssCollectionRenderer.
    *
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @param \Drupal\Core\KeyValueStore\StateInterface
    *   The state key/value store.
    */
-  public function __construct(KeyValueStoreInterface $state) {
+  public function __construct(StateInterface $state) {
     $this->state = $state;
   }
 
diff --git a/core/lib/Drupal/Core/Asset/JsCollectionOptimizer.php b/core/lib/Drupal/Core/Asset/JsCollectionOptimizer.php
index bf4cbf6..4d39a2e 100644
--- a/core/lib/Drupal/Core/Asset/JsCollectionOptimizer.php
+++ b/core/lib/Drupal/Core/Asset/JsCollectionOptimizer.php
@@ -6,8 +6,7 @@
 
 namespace Drupal\Core\Asset;
 
-use Drupal\Core\Asset\AssetCollectionOptimizerInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 
 
 /**
@@ -39,7 +38,7 @@ class JsCollectionOptimizer implements AssetCollectionOptimizerInterface {
   /**
    * The state key/value store.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -52,10 +51,10 @@ class JsCollectionOptimizer implements AssetCollectionOptimizerInterface {
    *   The optimizer for a single JS asset.
    * @param \Drupal\Core\Asset\AssetDumperInterface
    *   The dumper for optimized JS assets.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @param \Drupal\Core\KeyValueStore\StateInterface
    *   The state key/value store.
    */
-  public function __construct(AssetCollectionGrouperInterface $grouper, AssetOptimizerInterface $optimizer, AssetDumperInterface $dumper, KeyValueStoreInterface $state) {
+  public function __construct(AssetCollectionGrouperInterface $grouper, AssetOptimizerInterface $optimizer, AssetDumperInterface $dumper, StateInterface $state) {
     $this->grouper = $grouper;
     $this->optimizer = $optimizer;
     $this->dumper = $dumper;
diff --git a/core/lib/Drupal/Core/Asset/JsCollectionRenderer.php b/core/lib/Drupal/Core/Asset/JsCollectionRenderer.php
index 443387a..b9de5f8 100644
--- a/core/lib/Drupal/Core/Asset/JsCollectionRenderer.php
+++ b/core/lib/Drupal/Core/Asset/JsCollectionRenderer.php
@@ -6,8 +6,7 @@
 
 namespace Drupal\Core\Asset;
 
-use Drupal\Core\Asset\AssetCollectionRendererInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 
 /**
  * Renders JavaScript assets.
@@ -17,17 +16,17 @@ class JsCollectionRenderer implements AssetCollectionRendererInterface {
   /**
    * The state key/value store.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
   /**
    * Constructs a CssCollectionRenderer.
    *
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @param \Drupal\Core\KeyValueStore\StateInterface
    *   The state key/value store.
    */
-  public function __construct(KeyValueStoreInterface $state) {
+  public function __construct(StateInterface $state) {
     $this->state = $state;
   }
 
diff --git a/core/lib/Drupal/Core/Config/FileStorage.php b/core/lib/Drupal/Core/Config/FileStorage.php
index bf178c5..52c9aa5 100644
--- a/core/lib/Drupal/Core/Config/FileStorage.php
+++ b/core/lib/Drupal/Core/Config/FileStorage.php
@@ -204,11 +204,14 @@ public function listAll($prefix = '') {
       throw new StorageException($this->directory . '/ not found.');
     }
     $extension = '.' . static::getFileExtension();
-    $files = glob($this->directory . '/' . $prefix . '*' . $extension);
-    $clean_name = function ($value) use ($extension) {
-      return basename($value, $extension);
-    };
-    return array_map($clean_name, $files);
+    $files = new \GlobIterator(DRUPAL_ROOT . '/' . $this->directory . '/' . $prefix . '*' . $extension);
+
+    $names = array();
+    foreach ($files as $file) {
+      $names[] = $file->getBasename($extension);
+    }
+
+    return $names;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Config/InstallStorage.php b/core/lib/Drupal/Core/Config/InstallStorage.php
index e8442ea..16bcc1c 100644
--- a/core/lib/Drupal/Core/Config/InstallStorage.php
+++ b/core/lib/Drupal/Core/Config/InstallStorage.php
@@ -134,10 +134,9 @@ public function getComponentNames($type, array $list) {
     foreach ($list as $name) {
       $directory = $this->getComponentFolder($type, $name);
       if (file_exists($directory)) {
-        $files = glob($directory . '/*' . $extension);
-        foreach ($files as $filename) {
-          $name = basename($filename, $extension);
-          $folders[$name] = $directory;
+        $files = new \GlobIterator(DRUPAL_ROOT . '/' . $directory . '/*' . $extension);
+        foreach ($files as $file) {
+          $folders[$file->getBasename($extension)] = $directory;
         }
       }
     }
diff --git a/core/lib/Drupal/Core/Extension/CachedModuleHandler.php b/core/lib/Drupal/Core/Extension/CachedModuleHandler.php
index 6e09432..0def7f3 100644
--- a/core/lib/Drupal/Core/Extension/CachedModuleHandler.php
+++ b/core/lib/Drupal/Core/Extension/CachedModuleHandler.php
@@ -8,7 +8,7 @@
 namespace Drupal\Core\Extension;
 
 use Drupal\Core\Cache\CacheBackendInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 
 /**
  * Class that manages enabled modules in a Drupal installation.
@@ -18,7 +18,7 @@ class CachedModuleHandler extends ModuleHandler implements CachedModuleHandlerIn
   /**
    * State key/value store.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -39,7 +39,7 @@ class CachedModuleHandler extends ModuleHandler implements CachedModuleHandlerIn
   /**
    * Constructs a new CachedModuleHandler object.
    */
-  public function __construct(array $module_list = array(), KeyValueStoreInterface $state, CacheBackendInterface $bootstrap_cache) {
+  public function __construct(array $module_list = array(), StateInterface $state, CacheBackendInterface $bootstrap_cache) {
     parent::__construct($module_list);
     $this->state = $state;
     $this->bootstrapCache = $bootstrap_cache;
diff --git a/core/lib/Drupal/Core/KeyValueStore/State.php b/core/lib/Drupal/Core/KeyValueStore/State.php
new file mode 100644
index 0000000..36a7973
--- /dev/null
+++ b/core/lib/Drupal/Core/KeyValueStore/State.php
@@ -0,0 +1,125 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\KeyValueStore\StateInterface.
+ */
+
+namespace Drupal\Core\KeyValueStore;
+
+/**
+ * Provides the state system using a key value store.
+ */
+class State implements StateInterface {
+
+  /**
+   * The key value store to use.
+   *
+   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   */
+  protected $keyValueStore;
+
+  /**
+   * Static state cache.
+   *
+   * @var array
+   */
+  protected $cache = array();
+
+  /**
+   * Constructs a State object.
+   *
+   * @param \Drupal\Core\KeyValueStore\KeyValueFactory $key_value_factory
+   *  The key value store to use.
+   */
+  function __construct(KeyValueFactory $key_value_factory) {
+    $this->keyValueStore = $key_value_factory->get('state');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getMultiple(array $keys) {
+    $values = array();
+    $load = array();
+    foreach ($keys as $key) {
+      // Check if we have a value in the cache.
+      if (isset($this->cache[$key])) {
+        $values[$key] = $this->cache[$key];
+      }
+      // Load the value if we don't have an explicit NULL value.
+      elseif (!array_key_exists($key, $this->cache)) {
+        $load[] = $key;
+      }
+    }
+
+    if ($load) {
+      $loaded_values = $this->keyValueStore->getMultiple($load);
+      foreach ($load as $key) {
+        // If we find a value, even one that is NULL, add it to the cache and
+        // return it.
+        if (isset($loaded_values[$key]) || array_key_exists($key, $loaded_values)) {
+          $values[$key] = $loaded_values[$key];
+          $this->cache[$key] = $loaded_values[$key];
+        }
+        else {
+          $this->cache[$key] = NULL;
+        }
+      }
+    }
+
+    return $values;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function set($key, $value) {
+    $this->cache[$key] = $value;
+    $this->keyValueStore->set($key, $value);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteMultiple(array $keys) {
+    foreach ($keys as $key) {
+      unset($this->cache[$key]);
+    }
+    $this->keyValueStore->deleteMultiple($keys);
+  }
+
+
+  /**
+   * {@inheritdoc}
+   */
+  public function get($key, $default = NULL) {
+    $values = $this->getMultiple(array($key));
+    return isset($values[$key]) ? $values[$key] : $default;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setMultiple(array $data) {
+    foreach ($data as $key => $value) {
+      $this->cache[$key] = $value;
+    }
+    $this->keyValueStore->setMultiple($data);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function delete($key) {
+    $this->deleteMultiple(array($key));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function resetCache() {
+    $this->cache = array();
+  }
+
+}
diff --git a/core/lib/Drupal/Core/KeyValueStore/StateInterface.php b/core/lib/Drupal/Core/KeyValueStore/StateInterface.php
new file mode 100644
index 0000000..7584abc
--- /dev/null
+++ b/core/lib/Drupal/Core/KeyValueStore/StateInterface.php
@@ -0,0 +1,80 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\KeyValueStore\StateInterface.
+ */
+
+namespace Drupal\Core\KeyValueStore;
+
+/**
+ * Defines the interface for the state system.
+ */
+interface StateInterface {
+
+  /**
+   * Returns the stored value for a given key.
+   *
+   * @param string $key
+   *   The key of the data to retrieve.
+   * @param mixed $default
+   *   The default value to use if the key is not found.
+   *
+   * @return mixed
+   *   The stored value, or NULL if no value exists.
+   */
+  public function get($key, $default = NULL);
+
+  /**
+   * Returns the stored key/value pairs for a given set of keys.
+   *
+   * @param array $keys
+   *   A list of keys to retrieve.
+   *
+   * @return array
+   *   An associative array of items successfully returned, indexed by key.
+   */
+  public function getMultiple(array $keys);
+
+  /**
+   * Saves a value for a given key.
+   *
+   * @param string $key
+   *   The key of the data to store.
+   * @param mixed $value
+   *   The data to store.
+   */
+  public function set($key, $value);
+
+  /**
+   * Saves key/value pairs.
+   *
+   * @param array $data
+   *   An associative array of key/value pairs.
+   */
+  public function setMultiple(array $data);
+
+  /**
+   * Deletes an item.
+   *
+   * @param string $key
+   *   The item name to delete.
+   */
+  public function delete($key);
+
+  /**
+   * Deletes multiple items.
+   *
+   * @param array $keys
+   *   A list of item names to delete.
+   */
+  public function deleteMultiple(array $keys);
+
+  /**
+   * Resets the static cache.
+   *
+   * This is only needed for Simpletest.
+   */
+  public function resetCache();
+
+}
diff --git a/core/lib/Drupal/Core/Language/LanguageManager.php b/core/lib/Drupal/Core/Language/LanguageManager.php
index 532d404..e6526f2 100644
--- a/core/lib/Drupal/Core/Language/LanguageManager.php
+++ b/core/lib/Drupal/Core/Language/LanguageManager.php
@@ -9,7 +9,7 @@
 
 use Drupal\Component\Utility\MapArray;
 use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Symfony\Component\HttpFoundation\Request;
 
 /**
@@ -27,7 +27,7 @@ class LanguageManager {
   /**
    * The Key/Value Store to use for state.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state = NULL;
 
@@ -65,12 +65,12 @@ class LanguageManager {
   /**
    * Constructs an LanguageManager object.
    *
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   (optional) The state keyvalue store. Defaults to NULL.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   (optional) The module handler service. Defaults to NULL.
    */
-  public function __construct(KeyValueStoreInterface $state = NULL, ModuleHandlerInterface $module_handler = NULL) {
+  public function __construct(StateInterface $state = NULL, ModuleHandlerInterface $module_handler = NULL) {
     $this->state = $state;
     $this->moduleHandler = $module_handler;
   }
diff --git a/core/lib/Drupal/Core/Path/AliasManager.php b/core/lib/Drupal/Core/Path/AliasManager.php
index 72e5707..151bb23 100644
--- a/core/lib/Drupal/Core/Path/AliasManager.php
+++ b/core/lib/Drupal/Core/Path/AliasManager.php
@@ -21,13 +21,6 @@ class AliasManager implements AliasManagerInterface {
   protected $connection;
 
   /**
-   * The Key/Value Store to use for state
-   *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
-   */
-  protected $state;
-
-  /**
    * Language manager for retrieving the default langcode when none is specified.
    *
    * @var \Drupal\Core\Language\LanguageManager
diff --git a/core/lib/Drupal/Core/Path/AliasWhitelist.php b/core/lib/Drupal/Core/Path/AliasWhitelist.php
index 9e3a6a1..2c151b5 100644
--- a/core/lib/Drupal/Core/Path/AliasWhitelist.php
+++ b/core/lib/Drupal/Core/Path/AliasWhitelist.php
@@ -11,7 +11,7 @@
 use Drupal\Core\Cache\CacheCollector;
 use Drupal\Core\Database\Connection;
 use Drupal\Core\DestructableInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Lock\LockBackendInterface;
 use Drupal\Core\Utility\CacheArray;
 
@@ -23,7 +23,7 @@ class AliasWhitelist extends CacheCollector {
   /**
    * The Key/Value Store to use for state.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -43,12 +43,12 @@ class AliasWhitelist extends CacheCollector {
    *   The cache backend.
    * @param \Drupal\Core\Lock\LockBackendInterface $lock
    *   The lock backend.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state keyvalue store.
    * @param \Drupal\Core\Database\Connection $connection
    *   The database connection.
    */
-  public function __construct($cid, CacheBackendInterface $cache, LockBackendInterface $lock, KeyValueStoreInterface $state, Connection $connection) {
+  public function __construct($cid, CacheBackendInterface $cache, LockBackendInterface $lock, StateInterface $state, Connection $connection) {
     parent::__construct($cid, $cache, $lock);
     $this->state = $state;
     $this->connection = $connection;
diff --git a/core/lib/Drupal/Core/PrivateKey.php b/core/lib/Drupal/Core/PrivateKey.php
index fd8bb55..762a664 100644
--- a/core/lib/Drupal/Core/PrivateKey.php
+++ b/core/lib/Drupal/Core/PrivateKey.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Core;
 
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Component\Utility\Crypt;
 
 /**
@@ -18,17 +18,17 @@ class PrivateKey {
   /**
    * The state service.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
   /**
    * Constructs the token generator.
    *
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state service.
    */
-  function __construct(KeyValueStoreInterface $state) {
+  function __construct(StateInterface $state) {
     $this->state = $state;
   }
 
diff --git a/core/modules/action/action.views.inc b/core/modules/action/action.views.inc
index b38eead..9bdb3d3 100644
--- a/core/modules/action/action.views.inc
+++ b/core/modules/action/action.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provides views data for action.module.
+ * Provides views data and handlers for action.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/aggregator/aggregator.views.inc b/core/modules/aggregator/aggregator.views.inc
index 28e6b28..5d87034 100644
--- a/core/modules/aggregator/aggregator.views.inc
+++ b/core/modules/aggregator/aggregator.views.inc
@@ -3,6 +3,8 @@
 /**
  * @file
  * Provides views data for aggregator.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockLanguageTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockLanguageTest.php
index 2e4a4c6..9921f27 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockLanguageTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockLanguageTest.php
@@ -75,6 +75,7 @@ public function testLanguageBlockVisibility() {
 
     // Reset the static cache of the language list.
     drupal_static_reset('language_list');
+    \Drupal::state()->resetCache();
 
     // Check that a page has a block.
     $this->drupalget('', array('language' => language_load('en')));
diff --git a/core/modules/book/book.module b/core/modules/book/book.module
index c9fccf5..cd7d714 100644
--- a/core/modules/book/book.module
+++ b/core/modules/book/book.module
@@ -696,43 +696,28 @@ function template_preprocess_book_navigation(&$variables) {
   if ($book_link['mlid']) {
     $variables['tree'] = book_children($book_link);
 
-    $build = array();
-
     if ($prev = book_prev($book_link)) {
       $prev_href = url($prev['href']);
-      $build['#attached']['drupal_add_html_head_link'][][] = array(
-        'rel' => 'prev',
-        'href' => $prev_href,
-      );
+      drupal_add_html_head_link(array('rel' => 'prev', 'href' => $prev_href));
       $variables['prev_url'] = $prev_href;
       $variables['prev_title'] = check_plain($prev['title']);
     }
 
     if ($book_link['plid'] && $parent = book_link_load($book_link['plid'])) {
       $parent_href = url($parent['link_path']);
-      $build['#attached']['drupal_add_html_head_link'][][] = array(
-        'rel' => 'up',
-        'href' => $parent_href,
-      );
+      drupal_add_html_head_link(array('rel' => 'up', 'href' => $parent_href));
       $variables['parent_url'] = $parent_href;
       $variables['parent_title'] = check_plain($parent['title']);
     }
 
     if ($next = book_next($book_link)) {
       $next_href = url($next['href']);
-      $build['#attached']['drupal_add_html_head_link'][][] = array(
-        'rel' => 'next',
-        'href' => $next_href,
-      );
+      drupal_add_html_head_link(array('rel' => 'next', 'href' => $next_href));
       $variables['next_url'] = $next_href;
       $variables['next_title'] = check_plain($next['title']);
     }
   }
 
-  if (!empty($build)) {
-    drupal_render($build);
-  }
-
   $variables['has_links'] = FALSE;
   // Link variables to filter for values and set state of the flag variable.
   $links = array('prev_url', 'prev_title', 'parent_url', 'parent_title', 'next_url', 'next_title');
diff --git a/core/modules/ckeditor/lib/Drupal/ckeditor/Plugin/Editor/CKEditor.php b/core/modules/ckeditor/lib/Drupal/ckeditor/Plugin/Editor/CKEditor.php
index bc0dc61..3eefd37 100644
--- a/core/modules/ckeditor/lib/Drupal/ckeditor/Plugin/Editor/CKEditor.php
+++ b/core/modules/ckeditor/lib/Drupal/ckeditor/Plugin/Editor/CKEditor.php
@@ -320,9 +320,9 @@ public function getLangcodes() {
     if (empty($langcodes)) {
       $langcodes = array();
       // Collect languages included with CKEditor based on file listing.
-      $ckeditor_languages = glob(DRUPAL_ROOT . '/core/assets/vendor/ckeditor/lang/*.js');
-      foreach ($ckeditor_languages as $language_filename) {
-        $langcode = basename($language_filename, '.js');
+      $ckeditor_languages = new \GlobIterator(DRUPAL_ROOT . '/core/assets/vendor/ckeditor/lang/*.js');
+      foreach ($ckeditor_languages as $language_file) {
+        $langcode = $language_file->getBasename('.js');
         $langcodes[$langcode] = $langcode;
       }
       cache('ckeditor.languages')->set('langcodes', $langcodes);
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index fa38bfb..9f8b282 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -1731,20 +1731,3 @@ function comment_library_info() {
   );
   return $libraries;
 }
-
-/**
- * #post_render_cache callback; replaces the placeholder with the comment form.
- *
- * @param array $context
- *   An array with the following keys:
- *   - entity_type: an entity type
- *   - entity_id: an entity ID
- *   - field_name: a comment field name
- *
- * @return array $element
- *   The updated $element.
- */
-function comment_replace_form_placeholder(array $context) {
-  $entity = entity_load($context['entity_type'], $context['entity_id']);
-  return comment_add($entity, $context['field_name']);
-}
diff --git a/core/modules/comment/comment.views.inc b/core/modules/comment/comment.views.inc
index ed8f85a..663704b 100644
--- a/core/modules/comment/comment.views.inc
+++ b/core/modules/comment/comment.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for comment.module.
+ * Provide views data and handlers for comment.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php b/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
index be1b6db..ff0e346 100644
--- a/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
+++ b/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
@@ -138,24 +138,7 @@ public function viewElements(FieldItemListInterface $items) {
       if ($status == COMMENT_OPEN && $comment_settings['form_location'] == COMMENT_FORM_BELOW) {
         // Only show the add comment form if the user has permission.
         if ($this->currentUser->hasPermission('post comments')) {
-          // All users in the "anonymous" role can use the same form: it is fine
-          // for this form to be stored in the render cache.
-          if ($this->currentUser->isAnonymous()) {
-            $output['comment_form'] = comment_add($entity, $field_name);
-          }
-          // All other users need a user-specific form, which would break the
-          // render cache: hence use a #post_render_cache callback.
-          else {
-            $output['comment_form'] = array(
-              '#type' => 'render_cache_placeholder',
-              '#callback' => 'comment_replace_form_placeholder',
-              '#context' => array(
-                'entity_type' => $entity->entityType(),
-                'entity_id' => $entity->id(),
-                'field_name' => $field_name
-              ),
-            );
-          }
+          $output['comment_form'] = comment_add($entity, $field_name);
         }
       }
 
diff --git a/core/modules/contact/contact.views.inc b/core/modules/contact/contact.views.inc
index 1560362..6795b0e 100644
--- a/core/modules/contact/contact.views.inc
+++ b/core/modules/contact/contact.views.inc
@@ -3,6 +3,8 @@
 /**
  * @file
  * Provide views data for contact.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/contextual/contextual.views.inc b/core/modules/contextual/contextual.views.inc
index 528b3bb..ea8088a 100644
--- a/core/modules/contextual/contextual.views.inc
+++ b/core/modules/contextual/contextual.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for contextual.module.
+ * Provide views data and handlers for contextual.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/contextual/css/contextual.theme.css b/core/modules/contextual/css/contextual.theme.css
index 7475a1d..be6d44a 100644
--- a/core/modules/contextual/css/contextual.theme.css
+++ b/core/modules/contextual/css/contextual.theme.css
@@ -91,7 +91,9 @@
 }
 .contextual-region .contextual .contextual-links a {
   background-color: #fff;
-  color: #333;
+  /* This is an unfortunately necessary use of !important to prevent white
+   * links on a white background or some similar illegible combination. */
+  color: #333 !important;
   display: block;
   font-family: sans-serif;
   font-size: small;
diff --git a/core/modules/dblog/dblog.views.inc b/core/modules/dblog/dblog.views.inc
index 90be37c..2198783 100644
--- a/core/modules/dblog/dblog.views.inc
+++ b/core/modules/dblog/dblog.views.inc
@@ -3,6 +3,8 @@
 /**
  * @file
  * Provide views data for dblog.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/field/field.views.inc b/core/modules/field/field.views.inc
index ae87873..b2f33c1 100644
--- a/core/modules/field/field.views.inc
+++ b/core/modules/field/field.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide Views data for field.module.
+ * Provide Views data and handlers for field.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 use Drupal\Component\Utility\NestedArray;
diff --git a/core/modules/field/lib/Drupal/field/FieldInstanceStorageController.php b/core/modules/field/lib/Drupal/field/FieldInstanceStorageController.php
index 5d8fa9c..d88e6b1 100644
--- a/core/modules/field/lib/Drupal/field/FieldInstanceStorageController.php
+++ b/core/modules/field/lib/Drupal/field/FieldInstanceStorageController.php
@@ -16,7 +16,7 @@
 use Drupal\Component\Uuid\UuidInterface;
 use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Extension\ModuleHandler;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 
 /**
  * Controller class for field instances.
@@ -45,7 +45,7 @@ class FieldInstanceStorageController extends ConfigStorageController {
   /**
    * The state keyvalue collection.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -68,10 +68,10 @@ class FieldInstanceStorageController extends ConfigStorageController {
    *   The entity manager.
    * @param \Drupal\Core\Extension\ModuleHandler $module_handler
    *   The module handler.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state key value store.
    */
-  public function __construct($entity_type, array $entity_info, ConfigFactory $config_factory, StorageInterface $config_storage, QueryFactory $entity_query_factory, UuidInterface $uuid_service, EntityManagerInterface $entity_manager, ModuleHandler $module_handler, KeyValueStoreInterface $state) {
+  public function __construct($entity_type, array $entity_info, ConfigFactory $config_factory, StorageInterface $config_storage, QueryFactory $entity_query_factory, UuidInterface $uuid_service, EntityManagerInterface $entity_manager, ModuleHandler $module_handler, StateInterface $state) {
     parent::__construct($entity_type, $entity_info, $config_factory, $config_storage, $entity_query_factory, $uuid_service);
     $this->entityManager = $entity_manager;
     $this->moduleHandler = $module_handler;
diff --git a/core/modules/field/lib/Drupal/field/FieldStorageController.php b/core/modules/field/lib/Drupal/field/FieldStorageController.php
index 24db2c2..0da91aa 100644
--- a/core/modules/field/lib/Drupal/field/FieldStorageController.php
+++ b/core/modules/field/lib/Drupal/field/FieldStorageController.php
@@ -16,7 +16,7 @@
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Extension\ModuleHandler;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 
 /**
  * Controller class for fields.
@@ -40,7 +40,7 @@ class FieldStorageController extends ConfigStorageController {
   /**
    * The state keyvalue collection.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -63,10 +63,10 @@ class FieldStorageController extends ConfigStorageController {
    *   The entity manager.
    * @param \Drupal\Core\Extension\ModuleHandler $module_handler
    *   The module handler.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state key value store.
    */
-  public function __construct($entity_type, array $entity_info, ConfigFactory $config_factory, StorageInterface $config_storage, QueryFactory $entity_query_factory, UuidInterface $uuid_service, EntityManagerInterface $entity_manager, ModuleHandler $module_handler, KeyValueStoreInterface $state) {
+  public function __construct($entity_type, array $entity_info, ConfigFactory $config_factory, StorageInterface $config_storage, QueryFactory $entity_query_factory, UuidInterface $uuid_service, EntityManagerInterface $entity_manager, ModuleHandler $module_handler, StateInterface $state) {
     parent::__construct($entity_type, $entity_info, $config_factory, $config_storage, $entity_query_factory, $uuid_service);
     $this->entityManager = $entity_manager;
     $this->moduleHandler = $module_handler;
diff --git a/core/modules/file/file.views.inc b/core/modules/file/file.views.inc
index 7adc194..3ba4cc7 100644
--- a/core/modules/file/file.views.inc
+++ b/core/modules/file/file.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for file.module.
+ * Provide views data and handlers for file.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 use Drupal\Core\Entity\FieldableDatabaseStorageController;
diff --git a/core/modules/file/lib/Drupal/file/Tests/FileManagedTestBase.php b/core/modules/file/lib/Drupal/file/Tests/FileManagedTestBase.php
index 96305bd..b6fb820 100644
--- a/core/modules/file/lib/Drupal/file/Tests/FileManagedTestBase.php
+++ b/core/modules/file/lib/Drupal/file/Tests/FileManagedTestBase.php
@@ -38,6 +38,8 @@ function setUp() {
    *   'insert', etc.
    */
   function assertFileHooksCalled($expected) {
+    \Drupal::state()->resetCache();
+
     // Determine which hooks were called.
     $actual = array_keys(array_filter(file_test_get_all_calls()));
 
diff --git a/core/modules/forum/forum.views.inc b/core/modules/forum/forum.views.inc
index fa7174f..fb79907 100644
--- a/core/modules/forum/forum.views.inc
+++ b/core/modules/forum/forum.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for forum.module.
+ * Provide views data and handlers for forum.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/history/history.views.inc b/core/modules/history/history.views.inc
index 50e12aa..ed36820 100644
--- a/core/modules/history/history.views.inc
+++ b/core/modules/history/history.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for history.module.
+ * Provide views data and handlers for history.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/image/image.views.inc b/core/modules/image/image.views.inc
index 5babb6a..2fbcddb 100644
--- a/core/modules/image/image.views.inc
+++ b/core/modules/image/image.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for image.module.
+ * Provide views data and handlers for image.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 use Drupal\Core\Entity\FieldableDatabaseStorageController;
diff --git a/core/modules/language/lib/Drupal/language/Tests/LanguageConfigurationTest.php b/core/modules/language/lib/Drupal/language/Tests/LanguageConfigurationTest.php
index 1fb8c85..3381d44 100644
--- a/core/modules/language/lib/Drupal/language/Tests/LanguageConfigurationTest.php
+++ b/core/modules/language/lib/Drupal/language/Tests/LanguageConfigurationTest.php
@@ -72,6 +72,8 @@ function testLanguageConfiguration() {
     );
     $this->drupalPostForm(NULL, $edit, t('Save configuration'));
     $this->assertOptionSelected('edit-site-default-language', 'fr', 'Default language updated.');
+
+    \Drupal::state()->resetCache();
     $this->assertEqual($this->getUrl(), url('admin/config/regional/settings', array('absolute' => TRUE)), 'Correct page redirection.');
 
     // Check if a valid language prefix is added after changing the default
diff --git a/core/modules/language/lib/Drupal/language/Tests/LanguageFallbackTest.php b/core/modules/language/lib/Drupal/language/Tests/LanguageFallbackTest.php
index ba50def..4123fc0 100644
--- a/core/modules/language/lib/Drupal/language/Tests/LanguageFallbackTest.php
+++ b/core/modules/language/lib/Drupal/language/Tests/LanguageFallbackTest.php
@@ -26,7 +26,7 @@ public static function getInfo() {
   /**
    * The state storage service.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
diff --git a/core/modules/language/lib/Drupal/language/Tests/LanguageListTest.php b/core/modules/language/lib/Drupal/language/Tests/LanguageListTest.php
index 8b2190d..6b0f130 100644
--- a/core/modules/language/lib/Drupal/language/Tests/LanguageListTest.php
+++ b/core/modules/language/lib/Drupal/language/Tests/LanguageListTest.php
@@ -72,6 +72,7 @@ function testLanguageList() {
     );
     $this->drupalPostForm(NULL, $edit, t('Save configuration'));
     $this->assertNoOptionSelected('edit-site-default-language', 'en', 'Default language updated.');
+    \Drupal::state()->resetCache();
     $this->assertEqual($this->getUrl(), url($path, array('absolute' => TRUE)), 'Correct page redirection.');
 
     // Ensure we can't delete the default language.
@@ -96,6 +97,7 @@ function testLanguageList() {
       'site_default_language' => 'en',
     );
     $this->drupalPostForm($path, $edit, t('Save configuration'));
+    \Drupal::state()->resetCache();
     // Ensure 'delete' link works.
     $this->drupalGet('admin/config/regional/language');
     $this->clickLink(t('Delete'));
@@ -109,6 +111,7 @@ function testLanguageList() {
     // Delete the language for real. This a confirm form, we do not need any
     // fields changed.
     $this->drupalPostForm('admin/config/regional/language/delete/' . $langcode, array(), t('Delete'));
+    \Drupal::state()->resetCache();
     // We need raw here because %language and %langcode will add HTML.
     $t_args = array('%language' => $name, '%langcode' => $langcode);
     $this->assertRaw(t('The %language (%langcode) language has been removed.', $t_args), 'The test language has been removed.');
@@ -125,6 +128,7 @@ function testLanguageList() {
     $this->drupalPostForm('admin/config/regional/language/delete/fr', array(), t('Delete'));
     // Get the count of languages.
     drupal_static_reset('language_list');
+    \Drupal::state()->resetCache();
     $languages = language_list();
     // We need raw here because %language and %langcode will add HTML.
     $t_args = array('%language' => 'French', '%langcode' => 'fr');
@@ -149,6 +153,7 @@ function testLanguageList() {
       'direction' => '0',
     );
     $this->drupalPostForm('admin/config/regional/language/add', $edit, t('Add custom language'));
+    \Drupal::state()->resetCache();
     $this->assertEqual($this->getUrl(), url('admin/config/regional/language', array('absolute' => TRUE)), 'Correct page redirection.');
     $this->assertText($name, 'Name found.');
 
diff --git a/core/modules/locale/lib/Drupal/locale/Form/TranslateFormBase.php b/core/modules/locale/lib/Drupal/locale/Form/TranslateFormBase.php
index c33da33..ea4c9ce 100644
--- a/core/modules/locale/lib/Drupal/locale/Form/TranslateFormBase.php
+++ b/core/modules/locale/lib/Drupal/locale/Form/TranslateFormBase.php
@@ -11,7 +11,7 @@
 use Drupal\Core\Language\Language;
 use Drupal\Core\Language\LanguageManager;
 use Drupal\locale\StringStorageInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -31,7 +31,7 @@
   /**
    * The state store.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -54,12 +54,12 @@
    *
    * @param \Drupal\locale\StringStorageInterface $locale_storage
    *   The locale storage.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state service.
    * @param \Drupal\Core\Language\LanguageManager $language_manager
    *   The language manager.
    */
-  public function __construct(StringStorageInterface $locale_storage, KeyValueStoreInterface $state, LanguageManager $language_manager) {
+  public function __construct(StringStorageInterface $locale_storage, StateInterface $state, LanguageManager $language_manager) {
     $this->localeStorage = $locale_storage;
     $this->state = $state;
     $this->languageManager = $language_manager;
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
index 8cd217b..dff7ec3 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
@@ -136,6 +136,7 @@ function testStandalonePoFile() {
     $this->drupalPostForm('admin/config/regional/translate', $search, t('Filter'));
     $this->assertNoText(t('No strings available.'), 'String overwritten by imported string.');
     // This import should have changed number of plural forms.
+    \Drupal::state()->resetCache();
     $locale_plurals = \Drupal::state()->get('locale.translation.plurals') ?: array();
     $this->assert($locale_plurals['fr']['plurals'] == 3, 'Plural numbers changed.');
 
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleUpdateTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleUpdateTest.php
index 3d20f6d..1ed7800 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleUpdateTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleUpdateTest.php
@@ -130,6 +130,7 @@ function testUpdateCheckStatus() {
 
     // Get status of translation sources at both local and remote locations.
     $this->drupalGet('admin/reports/translations/check');
+    \Drupal::state()->resetCache();
     $result = locale_translation_get_status();
     $this->assertEqual($result['contrib_module_one']['de']->type, LOCALE_TRANSLATION_REMOTE, 'Translation of contrib_module_one found');
     $this->assertEqual($result['contrib_module_one']['de']->timestamp, $this->timestamp_new, 'Translation timestamp found');
diff --git a/core/modules/migrate/config/migrate.migration.d6_system_cron.yml b/core/modules/migrate/config/migrate.migration.d6_system_cron.yml
deleted file mode 100644
index 736af9b..0000000
--- a/core/modules/migrate/config/migrate.migration.d6_system_cron.yml
+++ /dev/null
@@ -1,13 +0,0 @@
-id: d6_system_cron
-source:
-    plugin: drupal6_variable
-    variables:
-        - cron_threshold_warning
-        - cron_threshold_error
-        - cron_last
-process:
-    'threshold:warning': cron_threshold_warning
-    'threshold:error': cron_threshold_error
-destination:
-    plugin: d8_config
-    config_name: system.cron
diff --git a/core/modules/migrate/config/migrate.migration.d6_system_rss.yml b/core/modules/migrate/config/migrate.migration.d6_system_rss.yml
deleted file mode 100644
index acce5e2..0000000
--- a/core/modules/migrate/config/migrate.migration.d6_system_rss.yml
+++ /dev/null
@@ -1,10 +0,0 @@
-id: d6_system_rss
-source:
-    plugin: drupal6_variable
-    variables:
-        - feed_default_items
-process:
-    'items:limit': feed_default_items
-destination:
-    plugin: d8_config
-    config_name: system.rss
diff --git a/core/modules/migrate/config/migrate.migration.d6_system_site.yml b/core/modules/migrate/config/migrate.migration.d6_system_site.yml
deleted file mode 100644
index bcfb712..0000000
--- a/core/modules/migrate/config/migrate.migration.d6_system_site.yml
+++ /dev/null
@@ -1,24 +0,0 @@
-id: d6_system_site
-source:
-    plugin: drupal6_variable
-    variables:
-        - site_name
-        - site_mail
-        - site_slogan
-        - site_frontpage
-        - site_403
-        - site_404
-        - drupal_weight_select_max
-        - admin_compact_mode
-process:
-    name: site_name
-    mail: site_mail
-    slogan: site_slogan
-    'page:front': site_frontpage
-    'page:403': site_403
-    'page:404': site_404
-    weight_select_max: drupal_weight_select_max
-    admin_compact_mode: admin_compact_mode
-destination:
-    plugin: d8_config
-    config_name: system.site
diff --git a/core/modules/migrate/lib/Drupal/migrate/Entity/Migration.php b/core/modules/migrate/lib/Drupal/migrate/Entity/Migration.php
deleted file mode 100644
index 5d48ed0..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Entity/Migration.php
+++ /dev/null
@@ -1,288 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Entity\Migration.
- */
-
-namespace Drupal\migrate\Entity;
-
-use Drupal\Core\Config\Entity\ConfigEntityBase;
-use Drupal\migrate\MigrateException;
-use Drupal\migrate\Plugin\MigrateIdMapInterface;
-
-/**
- * Defines the Migration entity.
- *
- * The migration entity stores the information about a single migration, like
- * the source, process and destination plugins.
- *
- * @EntityType(
- *   id = "migration",
- *   label = @Translation("Migration"),
- *   module = "migrate",
- *   controllers = {
- *     "storage" = "Drupal\Core\Config\Entity\ConfigStorageController",
- *     "list" = "Drupal\Core\Config\Entity\DraggableListController",
- *     "access" = "Drupal\Core\Entity\EntityAccessController",
- *     "form" = {
- *       "add" = "Drupal\Core\Entity\EntityFormController",
- *       "edit" = "Drupal\Core\Entity\EntityFormController",
- *       "delete" = "Drupal\Core\Entity\EntityFormController"
- *     }
- *   },
- *   config_prefix = "migrate.migration",
- *   entity_keys = {
- *     "id" = "id",
- *     "label" = "label",
- *     "weight" = "weight",
- *     "uuid" = "uuid"
- *   }
- * )
- */
-class Migration extends ConfigEntityBase implements MigrationInterface {
-
-  /**
-   * The migration ID (machine name).
-   *
-   * @var string
-   */
-  public $id;
-
-  /**
-   * The migration UUID.
-   *
-   * This is assigned automatically when the migration is created.
-   *
-   * @var string
-   */
-  public $uuid;
-
-  /**
-   * The human-readable label for the migration.
-   *
-   * @var string
-   */
-  public $label;
-
-  /**
-   * The plugin ID for the row.
-   *
-   * @var string
-   */
-  public $row;
-
-  /**
-   * The source configuration, with at least a 'plugin' key.
-   *
-   * Used to initialize the $sourcePlugin.
-   *
-   * @var array
-   */
-  public $source;
-
-  /**
-   * The source plugin.
-   *
-   * @var \Drupal\migrate\Plugin\MigrateSourceInterface
-   */
-  protected $sourcePlugin;
-
-  /**
-   * The configuration describing the process plugins.
-   *
-   * @var array
-   */
-  public $process;
-
-  /**
-   * The destination configuration, with at least a 'plugin' key.
-   *
-   * Used to initialize $destinationPlugin.
-   *
-   * @var array
-   */
-  public $destination;
-
-  /**
-   * The destination plugin.
-   *
-   * @var \Drupal\migrate\Plugin\MigrateDestinationInterface
-   */
-  protected $destinationPlugin;
-
-  /**
-   * The identifier map data.
-   *
-   * Used to initialize $idMapPlugin.
-   *
-   * @var string
-   */
-  public $idMap = array();
-
-  /**
-   * The identifier map.
-   *
-   * @var \Drupal\migrate\Plugin\MigrateIdMapInterface
-   */
-  protected $idMapPlugin;
-
-  /**
-   * The source identifiers.
-   *
-   * An array of source identifiers: the keys are the name of the properties,
-   * the values are dependent on the ID map plugin.
-   *
-   * @var array
-   */
-  public $sourceIds = array();
-
-  /**
-   * The destination identifiers.
-   *
-   * An array of destination identifiers: the keys are the name of the
-   * properties, the values are dependent on the ID map plugin.
-   *
-   * @var array
-   */
-  public $destinationIds = array();
-
-  /**
-   * Information on the highwater mark.
-   *
-   * @var array
-   */
-  public $highwaterProperty;
-
-  /**
-   * Indicate whether the primary system of record for this migration is the
-   * source, or the destination (Drupal). In the source case, migration of
-   * an existing object will completely replace the Drupal object with data from
-   * the source side. In the destination case, the existing Drupal object will
-   * be loaded, then changes from the source applied; also, rollback will not be
-   * supported.
-   *
-   * @var string
-   */
-  public $systemOfRecord = self::SOURCE;
-
-  /**
-   * Specify value of needs_update for current map row. Usually set by
-   * MigrateFieldHandler implementations.
-   *
-   * @var int
-   */
-  public $needsUpdate = MigrateIdMapInterface::STATUS_IMPORTED;
-
-  /**
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
-   */
-  protected $highwaterStorage;
-
-  /**
-   * @var bool
-   */
-  public $trackLastImported = FALSE;
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getSourcePlugin() {
-    if (!isset($this->sourcePlugin)) {
-      $this->sourcePlugin = \Drupal::service('plugin.manager.migrate.source')->createInstance($this->source['plugin'], $this->source, $this);
-    }
-    return $this->sourcePlugin;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getProcessPlugins(array $process = NULL) {
-    if (!isset($process)) {
-      $process = $this->process;
-    }
-    $process_plugins = array();
-    foreach ($this->getProcessNormalized($process) as $property => $configurations) {
-      $process_plugins[$property] = array();
-      foreach ($configurations as $configuration) {
-        if (isset($configuration['source'])) {
-          $process_plugins[$property][] = \Drupal::service('plugin.manager.migrate.process')->createInstance('get', $configuration, $this);
-        }
-        // Get is already handled.
-        if ($configuration['plugin'] != 'get') {
-          $process_plugins[$property][] = \Drupal::service('plugin.manager.migrate.process')->createInstance($configuration['plugin'], $configuration, $this);
-        }
-        if (!$process_plugins[$property]) {
-          throw new MigrateException("Invalid process configuration for $property");
-        }
-      }
-    }
-    return $process_plugins;
-  }
-
-  /**
-   * Resolve shorthands into a list of plugin configurations.
-   *
-   * @param array $process
-   *   A process configuration array.
-   *
-   * @return array
-   *   The normalized process configuration.
-   */
-  protected function getProcessNormalized(array $process) {
-    $normalized_configurations = array();
-    foreach ($process as $destination => $configuration) {
-      if (is_string($configuration)) {
-        $configuration = array(
-          'plugin' => 'get',
-          'source' => $configuration,
-        );
-      }
-      if (isset($configuration['plugin'])) {
-        $configuration = array($configuration);
-      }
-      $normalized_configurations[$destination] = $configuration;
-    }
-    return $normalized_configurations;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getDestinationPlugin() {
-    if (!isset($this->destinationPlugin)) {
-      $this->destinationPlugin = \Drupal::service('plugin.manager.migrate.destination')->createInstance($this->destination['plugin'], $this->destination, $this);
-    }
-    return $this->destinationPlugin;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getIdMap() {
-    if (!isset($this->idMapPlugin)) {
-      $configuration = $this->idMap;
-      $plugin = isset($configuration['plugin']) ? $configuration['plugin'] : 'sql';
-      $this->idMapPlugin = \Drupal::service('plugin.manager.migrate.id_map')->createInstance($plugin, $configuration, $this);
-    }
-    return $this->idMapPlugin;
-  }
-
-  /**
-   * @return \Drupal\Core\KeyValueStore\KeyValueStoreInterface
-   */
-  protected function getHighWaterStorage() {
-    if (!isset($this->highwaterStorage)) {
-      $this->highwaterStorage = \Drupal::keyValue('migrate:highwater');
-    }
-    return $this->highwaterStorage;
-  }
-
-  public function getHighwater() {
-    return $this->getHighWaterStorage()->get($this->id());
-  }
-
-  public function saveHighwater($highwater) {
-    $this->getHighWaterStorage()->set($this->id(), $highwater);
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Entity/MigrationInterface.php b/core/modules/migrate/lib/Drupal/migrate/Entity/MigrationInterface.php
deleted file mode 100644
index 1fa3dad..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Entity/MigrationInterface.php
+++ /dev/null
@@ -1,92 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Entity\MigrationInterface.
- */
-
-namespace Drupal\migrate\Entity;
-
-use Drupal\Core\Config\Entity\ConfigEntityInterface;
-
-/**
- * Interface for migrations.
- */
-interface MigrationInterface extends ConfigEntityInterface {
-
-  const SOURCE = 'source';
-  const DESTINATION = 'destination';
-
-  /**
-   * Codes representing the current status of a migration, and stored in the
-   * migrate_status table.
-   */
-  const STATUS_IDLE = 0;
-  const STATUS_IMPORTING = 1;
-  const STATUS_ROLLING_BACK = 2;
-  const STATUS_STOPPING = 3;
-  const STATUS_DISABLED = 4;
-
-  /**
-   * Message types to be passed to saveMessage() and saved in message tables.
-   * MESSAGE_INFORMATIONAL represents a condition that did not prevent the
-   * operation from succeeding - all others represent different severities of
-   * conditions resulting in a source record not being imported.
-   */
-  const MESSAGE_ERROR = 1;
-  const MESSAGE_WARNING = 2;
-  const MESSAGE_NOTICE = 3;
-  const MESSAGE_INFORMATIONAL = 4;
-
-  /**
-   * Codes representing the result of a rollback or import process.
-   */
-  const RESULT_COMPLETED = 1;   // All records have been processed
-  const RESULT_INCOMPLETE = 2;  // The process has interrupted itself (e.g., the
-                                // memory limit is approaching)
-  const RESULT_STOPPED = 3;     // The process was stopped externally (e.g., via
-                                // drush migrate-stop)
-  const RESULT_FAILED = 4;      // The process had a fatal error
-  const RESULT_SKIPPED = 5;     // Dependencies are unfulfilled - skip the process
-  const RESULT_DISABLED = 6;    // This migration is disabled, skipping
-
-  /**
-   * Returns the initialized source plugin.
-   *
-   * @return \Drupal\migrate\Plugin\MigrateSourceInterface
-   */
-  public function getSourcePlugin();
-
-  /**
-   * Returns the process plugins.
-   *
-   * @param array $process
-   *   A process configuration array.
-   *
-   * @return array
-   *   A list of process plugins.
-   */
-  public function getProcessPlugins(array $process = NULL);
-
-  /**
-   * Returns the initialized destination plugin.
-   *
-   * @return \Drupal\migrate\Plugin\MigrateDestinationInterface
-   */
-  public function getDestinationPlugin();
-
-  /**
-   * Returns the initialized id_map plugin.
-   *
-   * @return \Drupal\migrate\Plugin\MigrateIdMapInterface
-   */
-  public function getIdMap();
-
-  /**
-   * @return int
-   */
-  public function getHighwater();
-
-  public function saveHighwater($highwater);
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/MigrateException.php b/core/modules/migrate/lib/Drupal/migrate/MigrateException.php
deleted file mode 100644
index d07c04f..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/MigrateException.php
+++ /dev/null
@@ -1,75 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\MigrateException.
- */
-
-namespace Drupal\migrate;
-
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\Plugin\MigrateIdMapInterface;
-
-/**
- * Defines the migrate exception class.
- */
-class MigrateException extends \Exception {
-
-  /**
-   * The level of the error being reported.
-   *
-   * The value is a Migration::MESSAGE_* constant.
-   *
-   * @var int
-   */
-  protected $level;
-
-  /**
-   * The status to record in the map table for the current item.
-   *
-   * The value is a MigrateMap::STATUS_* constant.
-   *
-   * @var int
-   */
-  protected $status;
-
-  /**
-   * Constructs a MigrateException object.
-   *
-   * @param string $message
-   *   The message for the exception.
-   * @param int $code
-   *   The Exception code.
-   * @param \Exception $previous
-   *   The previous exception used for the exception chaining.
-   * @param int $level
-   *   The level of the error, a Migration::MESSAGE_* constant.
-   * @param int $status
-   *   The status of the item for the map table, a MigrateMap::STATUS_*
-   *   constant.
-   */
-  public function __construct($message = null, $code = 0, \Exception $previous = null, $level = MigrationInterface::MESSAGE_ERROR, $status = MigrateIdMapInterface::STATUS_FAILED) {
-    $this->level = $level;
-    $this->status = $status;
-    parent::__construct($message);
-  }
-
-  /**
-   * Gets the level.
-   *
-   * @return int
-   */
-  public function getLevel() {
-    return $this->level;
-  }
-
-  /**
-   * Gets the status of the current item.
-   *
-   * @return int
-   */
-  public function getStatus() {
-    return $this->status;
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/MigrateExecutable.php b/core/modules/migrate/lib/Drupal/migrate/MigrateExecutable.php
deleted file mode 100644
index 9246ffe..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/MigrateExecutable.php
+++ /dev/null
@@ -1,538 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\MigrateExecutable.
- */
-
-namespace Drupal\migrate;
-
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\Plugin\MigrateIdMapInterface;
-
-/**
- * Defines a migrate executable class.
- */
-class MigrateExecutable {
-
-  /**
-   * The migration to do.
-   *
-   * @var \Drupal\migrate\Entity\MigrationInterface
-   */
-  protected $migration;
-
-  /**
-   * The number of successfully imported rows since feedback was given.
-   *
-   * @var int
-   */
-  protected $successes_since_feedback;
-
-  /**
-   * The number of rows that were successfully processed.
-   *
-   * @var int
-   */
-  protected $total_successes;
-
-  /**
-   * Status of one row.
-   *
-   * The value is a MigrateIdMapInterface::STATUS_* constant, for example:
-   * STATUS_IMPORTED.
-   *
-   * @var int
-   */
-  protected $needsUpdate;
-
-  /**
-   * The number of rows processed.
-   *
-   * The total attempted, whether or not they were successful.
-   *
-   * @var int
-   */
-  protected $total_processed;
-
-  /**
-   * The queued messages not yet saved.
-   *
-   * Each element in the array is an array with two keys:
-   * - 'message': The message string.
-   * - 'level': The level, a MigrationInterface::MESSAGE_* constant.
-   *
-   * @var array
-   */
-  protected $queuedMessages = array();
-
-  /**
-   * The options that can be set when executing the migration.
-   *
-   * Values can be set for:
-   * - 'limit': Sets a time limit.
-   *
-   * @var array
-   */
-  protected $options;
-
-  /**
-   * The fraction of the memory limit at which an operation will be interrupted.
-   * Can be overridden by a Migration subclass if one would like to push the
-   * envelope. Defaults to 85%.
-   *
-   * @var float
-   */
-  protected $memoryThreshold = 0.85;
-
-  /**
-   * The PHP memory_limit expressed in bytes.
-   *
-   * @var int
-   */
-  protected $memoryLimit;
-
-  /**
-   * The fraction of the time limit at which an operation will be interrupted.
-   * Can be overridden by a Migration subclass if one would like to push the
-   * envelope. Defaults to 90%.
-   *
-   * @var float
-   */
-  protected $timeThreshold = 0.90;
-
-  /**
-   * The PHP max_execution_time.
-   *
-   * @var int
-   */
-  protected $timeLimit;
-
-  /**
-   * @var array
-   */
-  protected $sourceIdValues;
-
-  /**
-   * @var int
-   */
-  protected $processed_since_feedback = 0;
-
-  /**
-   * The translation manager.
-   *
-   * @var \Drupal\Core\StringTranslation\TranslationInterface
-   */
-  protected $translationManager;
-
-  /**
-   * @param MigrationInterface $migration
-   * @param MigrateMessageInterface $message
-   *
-   * @throws \Drupal\migrate\MigrateException
-   */
-  public function __construct(MigrationInterface $migration, MigrateMessageInterface $message) {
-    $this->migration = $migration;
-    $this->message = $message;
-    $this->migration->getIdMap()->setMessage($message);
-    // Record the memory limit in bytes
-    $limit = trim(ini_get('memory_limit'));
-    if ($limit == '-1') {
-      $this->memoryLimit = PHP_INT_MAX;
-    }
-    else {
-      if (!is_numeric($limit)) {
-        $last = strtolower(substr($limit, -1));
-        switch ($last) {
-          case 'g':
-            $limit *= 1024;
-          case 'm':
-            $limit *= 1024;
-          case 'k':
-            $limit *= 1024;
-            break;
-          default:
-            throw new MigrateException($this->t('Invalid PHP memory_limit !limit',
-              array('!limit' => $limit)));
-        }
-      }
-      $this->memoryLimit = $limit;
-    }
-  }
-
-  /**
-   * @return \Drupal\migrate\Source
-   */
-  public function getSource() {
-    if (!isset($this->source)) {
-      $this->source = new Source($this->migration, $this);
-    }
-    return $this->source;
-  }
-
-  /**
-   * The rollback action to be saved for the current row.
-   *
-   * @var int
-   */
-  public $rollbackAction;
-
-  /**
-   * An array of counts. Initially used for cache hit/miss tracking.
-   *
-   * @var array
-   */
-  protected $counts = array();
-
-  /**
-   * When performing a bulkRollback(), the maximum number of items to pass in
-   * a single call. Can be overridden in derived class constructor.
-   *
-   * @var int
-   */
-  protected $rollbackBatchSize = 50;
-
-  /**
-   * The object currently being constructed
-   * @var \stdClass
-   */
-  protected $destinationValues;
-
-  /**
-   * The current data row retrieved from the source.
-   * @var \stdClass
-   */
-  protected $sourceValues;
-
-  /**
-   * Perform an import operation - migrate items from source to destination.
-   */
-  public function import() {
-    $return = MigrationInterface::RESULT_COMPLETED;
-    $source = $this->getSource();
-    $destination = $this->migration->getDestinationPlugin();
-    $id_map = $this->migration->getIdMap();
-
-    try {
-      $source->rewind();
-    }
-    catch (\Exception $e) {
-      $this->message->display(
-        $this->t('Migration failed with source plugin exception: !e',
-          array('!e' => $e->getMessage())));
-      return MigrationInterface::RESULT_FAILED;
-    }
-    while ($source->valid()) {
-      $row = $source->current();
-      if ($this->sourceIdValues = $row->getSourceIdValues()) {
-        // Wipe old messages, and save any new messages.
-        $id_map->delete($row->getSourceIdValues(), TRUE);
-        $this->saveQueuedMessages();
-      }
-
-      $this->processRow($row);
-
-      try {
-        $destination_id_values = $destination->import($row);
-        // @TODO handle the successful but no ID case like config.
-        if ($destination_id_values) {
-          $id_map->saveIdMapping($row, $destination_id_values, $this->needsUpdate, $this->rollbackAction);
-          $this->successes_since_feedback++;
-          $this->total_successes++;
-        }
-        else {
-          $id_map->saveIdMapping($row, array(), MigrateIdMapInterface::STATUS_FAILED, $this->rollbackAction);
-          if ($id_map->messageCount() == 0) {
-            $message = $this->t('New object was not saved, no error provided');
-            $this->saveMessage($message);
-            $this->message->display($message);
-          }
-        }
-      }
-      catch (MigrateException $e) {
-        $this->migration->getIdMap()->saveIdMapping($row, array(), $e->getStatus(), $this->rollbackAction);
-        $this->saveMessage($e->getMessage(), $e->getLevel());
-        $this->message->display($e->getMessage());
-      }
-      catch (\Exception $e) {
-        $this->migration->getIdMap()->saveIdMapping($row, array(), MigrateIdMapInterface::STATUS_FAILED, $this->rollbackAction);
-        $this->handleException($e);
-      }
-      $this->total_processed++;
-      $this->processed_since_feedback++;
-      if ($highwater_property = $this->migration->get('highwaterProperty')) {
-        $this->migration->saveHighwater($row->getSourceProperty($highwater_property['name']));
-      }
-
-      // Reset row properties.
-      unset($sourceValues, $destinationValues);
-      $this->needsUpdate = MigrateIdMapInterface::STATUS_IMPORTED;
-
-      // TODO: Temporary. Remove when http://drupal.org/node/375494 is committed.
-      // TODO: Should be done in MigrateDestinationEntity
-      if (!empty($destination->entityType)) {
-        entity_get_controller($destination->entityType)->resetCache();
-      }
-
-      if (($return = $this->checkStatus()) != MigrationInterface::RESULT_COMPLETED) {
-        break;
-      }
-      if ($this->timeOptionExceeded()) {
-        break;
-      }
-      try {
-        $source->next();
-      }
-      catch (\Exception $e) {
-        $this->message->display(
-          $this->t('Migration failed with source plugin exception: !e',
-            array('!e' => $e->getMessage())));
-        return MigrationInterface::RESULT_FAILED;
-      }
-    }
-
-    /**
-     * @TODO uncomment this
-     */
-    #$this->progressMessage($return);
-
-    return $return;
-  }
-
-  /**
-   * @param Row $row
-   *   The $row to be processed.
-   * @param array $process
-   *   A process pipeline configuration. If not set, the top level process
-   *   configuration in the migration entity is used.
-   * @param mixed $value
-   *   Optional initial value of the pipeline for the first destination.
-   *   Usually setting this is not necessary as $process typically starts with
-   *   a 'get'. This is useful only when the $process contains a single
-   *   destination and needs to access a value outside of the source. See
-   *   \Drupal\migrate\Plugin\migrate\process\Iterator::transformKey for an
-   *   example.
-   */
-  public function processRow(Row $row, array $process = NULL, $value = NULL) {
-    foreach ($this->migration->getProcessPlugins($process) as $destination => $plugins) {
-      foreach ($plugins as $plugin) {
-        $value = $plugin->transform($value, $this, $row, $destination);
-      }
-      $row->setDestinationProperty($destination, $value);
-      // Reset the value.
-      $value = NULL;
-    }
-  }
-
-  /**
-   * Fetch the key array for the current source record.
-   *
-   * @return array
-   */
-  protected function currentSourceIds() {
-    return $this->getSource()->getCurrentIds();
-  }
-
-  /**
-   * Test whether we've exceeded the designated time limit.
-   *
-   * @return boolean
-   *  TRUE if the threshold is exceeded, FALSE if not.
-   */
-  protected function timeOptionExceeded() {
-    if (!$time_limit = $this->getTimeLimit()) {
-      return FALSE;
-    }
-    $time_elapsed = time() - REQUEST_TIME;
-    if ($time_elapsed >= $time_limit) {
-      return TRUE;
-    }
-    else {
-      return FALSE;
-    }
-  }
-
-  public function getTimeLimit() {
-    if (isset($this->options['limit']) &&
-        ($this->options['limit']['unit'] == 'seconds' || $this->options['limit']['unit'] == 'second')) {
-      return $this->options['limit']['value'];
-    }
-    else {
-      return NULL;
-    }
-  }
-
-  /**
-   * Pass messages through to the map class.
-   *
-   * @param string $message
-   *  The message to record.
-   * @param int $level
-   *  Optional message severity (defaults to MESSAGE_ERROR).
-   */
-  public function saveMessage($message, $level = MigrationInterface::MESSAGE_ERROR) {
-    $this->migration->getIdMap()->saveMessage($this->sourceIdValues, $message, $level);
-  }
-
-  /**
-   * Queue messages to be later saved through the map class.
-   *
-   * @param string $message
-   *  The message to record.
-   * @param int $level
-   *  Optional message severity (defaults to MESSAGE_ERROR).
-   */
-  public function queueMessage($message, $level = MigrationInterface::MESSAGE_ERROR) {
-    $this->queuedMessages[] = array('message' => $message, 'level' => $level);
-  }
-
-  /**
-   * Save any messages we've queued up to the message table.
-   */
-  public function saveQueuedMessages() {
-    foreach ($this->queuedMessages as $queued_message) {
-      $this->saveMessage($queued_message['message'], $queued_message['level']);
-    }
-    $this->queuedMessages = array();
-  }
-
-  /**
-   * Standard top-of-loop stuff, common between rollback and import - check
-   * for exceptional conditions, and display feedback.
-   */
-  protected function checkStatus() {
-    if ($this->memoryExceeded()) {
-      return MigrationInterface::RESULT_INCOMPLETE;
-    }
-    if ($this->timeExceeded()) {
-      return MigrationInterface::RESULT_INCOMPLETE;
-    }
-    /*
-     * @TODO uncomment this
-    if ($this->getStatus() == MigrationInterface::STATUS_STOPPING) {
-      return MigrationBase::RESULT_STOPPED;
-    }
-    */
-    // If feedback is requested, produce a progress message at the proper time
-    /*
-     * @TODO uncomment this
-    if (isset($this->feedback)) {
-      if (($this->feedback_unit == 'seconds' && time() - $this->lastfeedback >= $this->feedback) ||
-          ($this->feedback_unit == 'items' && $this->processed_since_feedback >= $this->feedback)) {
-        $this->progressMessage(MigrationInterface::RESULT_INCOMPLETE);
-      }
-    }
-    */
-
-    return MigrationInterface::RESULT_COMPLETED;
-  }
-
-  /**
-   * Test whether we've exceeded the desired memory threshold. If so, output a message.
-   *
-   * @return boolean
-   *  TRUE if the threshold is exceeded, FALSE if not.
-   */
-  protected function memoryExceeded() {
-    $usage = memory_get_usage();
-    $pct_memory = $usage / $this->memoryLimit;
-    if ($pct_memory > $this->memoryThreshold) {
-      $this->message->display(
-        $this->t('Memory usage is !usage (!pct% of limit !limit), resetting statics',
-          array('!pct' => round($pct_memory*100),
-                '!usage' => format_size($usage),
-                '!limit' => format_size($this->memoryLimit))),
-        'warning');
-      // First, try resetting Drupal's static storage - this frequently releases
-      // plenty of memory to continue
-      drupal_static_reset();
-      $usage = memory_get_usage();
-      $pct_memory = $usage/$this->memoryLimit;
-      // Use a lower threshold - we don't want to be in a situation where we keep
-      // coming back here and trimming a tiny amount
-      if ($pct_memory > (.90 * $this->memoryThreshold)) {
-        $this->message->display(
-          $this->t('Memory usage is now !usage (!pct% of limit !limit), not enough reclaimed, starting new batch',
-            array('!pct' => round($pct_memory*100),
-                  '!usage' => format_size($usage),
-                  '!limit' => format_size($this->memoryLimit))),
-          'warning');
-        return TRUE;
-      }
-      else {
-        $this->message->display(
-          $this->t('Memory usage is now !usage (!pct% of limit !limit), reclaimed enough, continuing',
-            array('!pct' => round($pct_memory*100),
-                  '!usage' => format_size($usage),
-                  '!limit' => format_size($this->memoryLimit))),
-          'warning');
-        return FALSE;
-      }
-    }
-    else {
-      return FALSE;
-    }
-  }
-
-  /**
-   * Test whether we're approaching the PHP time limit.
-   *
-   * @return boolean
-   *  TRUE if the threshold is exceeded, FALSE if not.
-   */
-  protected function timeExceeded() {
-    if ($this->timeLimit == 0) {
-      return FALSE;
-    }
-    $time_elapsed = time() - REQUEST_TIME;
-    $pct_time = $time_elapsed / $this->timeLimit;
-    if ($pct_time > $this->timeThreshold) {
-      return TRUE;
-    }
-    else {
-      return FALSE;
-    }
-  }
-
-  /**
-   * Takes an Exception object and both saves and displays it, pulling additional
-   * information on the location triggering the exception.
-   *
-   * @param \Exception $exception
-   *  Object representing the exception.
-   * @param boolean $save
-   *  Whether to save the message in the migration's mapping table. Set to FALSE
-   *  in contexts where this doesn't make sense.
-   */
-  public function handleException($exception, $save = TRUE) {
-    $result = _drupal_decode_exception($exception);
-    $message = $result['!message'] . ' (' . $result['%file'] . ':' . $result['%line'] . ')';
-    if ($save) {
-      $this->saveMessage($message);
-    }
-    $this->message->display($message);
-  }
-
-  /**
-   * Translates a string to the current language or to a given language.
-   *
-   * See the t() documentation for details.
-   */
-  protected function t($string, array $args = array(), array $options = array()) {
-    return $this->translationManager()->translate($string, $args, $options);
-  }
-
-  /**
-   * Gets the translation manager.
-   *
-   * @return \Drupal\Core\StringTranslation\TranslationInterface
-   *   The translation manager.
-   */
-  protected function translationManager() {
-    if (!$this->translationManager) {
-      $this->translationManager = \Drupal::translation();
-    }
-    return $this->translationManager;
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/MigrateMessage.php b/core/modules/migrate/lib/Drupal/migrate/MigrateMessage.php
deleted file mode 100644
index d90297e..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/MigrateMessage.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\MigrateMessage.
- */
-
-namespace Drupal\migrate;
-
-/**
- * Defines a migrate message class.
- */
-class MigrateMessage implements MigrateMessageInterface {
-
-  /**
-   * Displays a migrate message.
-   *
-   * @param string $message
-   *   The message to display.
-   * @param string $type
-   *   The type of message, for example: status or warning.
-   */
-  function display($message, $type = 'status') {
-    drupal_set_message($message, $type);
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/MigrateMessageInterface.php b/core/modules/migrate/lib/Drupal/migrate/MigrateMessageInterface.php
deleted file mode 100644
index bcf3753..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/MigrateMessageInterface.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-/**
- * @file
- * Contains
- */
-
-namespace Drupal\migrate;
-
-
-interface MigrateMessageInterface {
-
-  /**
-   * @param $message
-   * @param string $type
-   *
-   * @return mixed
-   */
-  function display($message, $type = 'status');
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateDestinationInterface.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateDestinationInterface.php
deleted file mode 100644
index 97ede97..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateDestinationInterface.php
+++ /dev/null
@@ -1,63 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\MigrateDestinationInterface.
- */
-
-namespace Drupal\migrate\Plugin;
-
-use Drupal\Component\Plugin\PluginInspectionInterface;
-use Drupal\migrate\Entity\Migration;
-use Drupal\migrate\Row;
-
-/**
- * Destinations are responsible for persisting source data into the destination
- * Drupal.
- */
-interface MigrateDestinationInterface extends PluginInspectionInterface {
-
-  /**
-   * To support MigrateIdMap maps, derived destination classes should return
-   * schema field definition(s) corresponding to the primary key of the destination
-   * being implemented. These are used to construct the destination key fields
-   * of the map table for a migration using this destination.
-   */
-  public function getIdsSchema();
-
-  /**
-   * Derived classes must implement fields(), returning a list of available
-   * destination fields.
-   *
-   * @todo Review the cases where we need the Migration parameter, can we avoid that?
-   *
-   * @param Migration $migration
-   *   Optionally, the migration containing this destination.
-   * @return array
-   *  - Keys: machine names of the fields
-   *  - Values: Human-friendly descriptions of the fields.
-   */
-  public function fields(Migration $migration = NULL);
-
-  /**
-   * Derived classes may implement preImport() and/or postImport(), to do any
-   * processing they need done before or after looping over all source rows.
-   * Similarly, preRollback() or postRollback() may be implemented.
-   */
-  public function preImport();
-  public function preRollback();
-  public function postImport();
-  public function postRollback();
-
-  /**
-   * Derived classes must implement import(), to construct one new object (pre-populated
-   * using ID mappings in the Migration).
-   */
-  public function import(Row $row);
-
-  /**
-   * Delete the specified IDs from the target Drupal.
-   * @param array $destination_identifiers
-   */
-  public function rollbackMultiple(array $destination_identifiers);
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateIdMapInterface.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateIdMapInterface.php
deleted file mode 100644
index 53c6ff5..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateIdMapInterface.php
+++ /dev/null
@@ -1,241 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\MigrateIdMapInterface.
- */
-
-namespace Drupal\migrate\Plugin;
-
-use Drupal\Component\Plugin\PluginInspectionInterface;
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\MigrateMessageInterface;
-use Drupal\migrate\Row;
-
-/**
- * Defines an interface for migrate ID mappings.
- *
- * Migrate ID mappings maintain a relation between source ID and destination ID
- * for audit and rollback purposes.
- */
-interface MigrateIdMapInterface extends PluginInspectionInterface {
-
-  /**
-   * Codes reflecting the current status of a map row.
-   */
-  const STATUS_IMPORTED = 0;
-  const STATUS_NEEDS_UPDATE = 1;
-  const STATUS_IGNORED = 2;
-  const STATUS_FAILED = 3;
-
-  /**
-   * Codes reflecting how to handle the destination item on rollback.
-   */
-  const ROLLBACK_DELETE = 0;
-  const ROLLBACK_PRESERVE = 1;
-
-  /**
-   * Saves a mapping from the source identifiers to the destination identifiers.
-   *
-   * Called upon import of one row, we record a mapping from the source ID
-   * to the destination ID. Also may be called, setting the third parameter to
-   * NEEDS_UPDATE, to signal an existing record should be re-migrated.
-   *
-   * @param \Drupal\migrate\Row $row
-   *   The raw source data. We use the ID map derived from the source object
-   *   to get the source identifier values.
-   * @param array $destination_id_values
-   *   An array of destination identifier values.
-   * @param int $status
-   *   Status of the source row in the map.
-   * @param int $rollback_action
-   *   How to handle the destination object on rollback.
-   */
-  public function saveIdMapping(Row $row, array $destination_id_values, $status = self::STATUS_IMPORTED, $rollback_action = self::ROLLBACK_DELETE);
-
-  /**
-   * Saves a message related to a source record in the migration message table.
-   *
-   * @param array $source_id_values
-   *   The source identifier values of the record in error.
-   * @param string $message
-   *   The message to record.
-   * @param int $level
-   *   Optional message severity (defaults to MESSAGE_ERROR).
-   */
-  public function saveMessage(array $source_id_values, $message, $level = MigrationInterface::MESSAGE_ERROR);
-
-  /**
-   * Prepares to run a full update.
-   *
-   * Prepares this migration to run as an update - that is, in addition to
-   * unmigrated content (source records not in the map table) being imported,
-   * previously-migrated content will also be updated in place by marking all
-   * previously-imported content as ready to be re-imported.
-   */
-  public function prepareUpdate();
-
-  /**
-   * Returns the number of processed items in the map.
-   *
-   * @return int
-   *   The count of records in the map table.
-   */
-  public function processedCount();
-
-  /**
-   * Returns the number of imported items in the map.
-   *
-   * @return int
-   *   The number of imported items.
-   */
-  public function importedCount();
-
-
-  /**
-   * Returns a count of items which are marked as needing update.
-   *
-   * @return int
-   *   The number of items which need updating.
-   */
-  public function updateCount();
-
-  /**
-   * Returns the number of items that failed to import.
-   *
-   * @return int
-   *   The number of items that errored out.
-   */
-  public function errorCount();
-
-  /**
-   * Returns the number of messages saved.
-   *
-   * @return int
-   *   The number of messages.
-   */
-  public function messageCount();
-
-  /**
-   * Deletes the map and message entries for a given source record.
-   *
-   * @param array $source_id_values
-   *   The source identifier values of the record to delete.
-   * @param bool $messages_only
-   *   TRUE to only delete the migrate messages.
-   */
-  public function delete(array $source_id_values, $messages_only = FALSE);
-
-  /**
-   * Deletes the map and message table entries for a given destination row.
-   *
-   * @param array $destination_id_values
-   *   The destination identifier values we should do the deletes for.
-   */
-  public function deleteDestination(array $destination_id_values);
-
-  /**
-   * Deletes the map and message entries for a set of given source records.
-   *
-   * @param array $source_id_values
-   *   The identifier values of the sources we should do the deletes for. Each
-   *   array member is an array of identifier values for one source row.
-   */
-  public function deleteBulk(array $source_id_values);
-
-  /**
-   * Clears all messages from the map.
-   */
-  public function clearMessages();
-
-  /**
-   * Retrieves a row from the map table based on source identifier values.
-   *
-   * @param array $source_id_values
-   *   The source identifier values of the record to retrieve.
-   *
-   * @return array
-   *   The raw row data as an associative array.
-   */
-  public function getRowBySource(array $source_id_values);
-
-  /**
-   * Retrieves a row by the destination identifiers.
-   *
-   * @param array $destination_id_values
-   *   The destination identifier values of the record to retrieve.
-   *
-   * @return array
-   *   The row(s) of data.
-   */
-  public function getRowByDestination(array $destination_id_values);
-
-  /**
-   * Retrieves an array of map rows marked as needing update.
-   *
-   * @param int $count
-   *   The maximum number of rows to return.
-   *
-   * @return array
-   *   Array of map row objects that need updating.
-   */
-  public function getRowsNeedingUpdate($count);
-
-  /**
-   * Looks up the source identifier.
-   *
-   * Given a (possibly multi-field) destination identifier value, return the
-   * (possibly multi-field) source identifier value mapped to it.
-   *
-   * @param array $destination_id_values
-   *   The destination identifier values of the record.
-   *
-   * @return array
-   *   The source identifier values of the record, or NULL on failure.
-   */
-  public function lookupSourceID(array $destination_id_values);
-
-  /**
-   * Looks up the destination identifier.
-   *
-   * Given a (possibly multi-field) source identifier value, return the
-   * (possibly multi-field) destination identifier value it is mapped to.
-   *
-   * @param array $destination_id_values
-   *   The source identifier values of the record.
-   *
-   * @return array
-   *   The destination identifier values of the record, or NULL on failure.
-   */
-  public function lookupDestinationID(array $source_id_values);
-
-  /**
-   * Removes any persistent storage used by this map.
-   *
-   * For example, remove the map and message tables.
-   */
-  public function destroy();
-
-  /**
-   * Gets the qualified map table.
-   *
-   * @todo Remove this as this is SQL only and so doesn't belong to the interface.
-   */
-  public function getQualifiedMapTable();
-
-  /**
-   * Sets the migrate message.
-   *
-   * @param \Drupal\migrate\MigrateMessageInterface $message
-   *   The message to display.
-   */
-  public function setMessage(MigrateMessageInterface $message);
-
-  /**
-   * Sets a specified record to be updated, if it exists.
-   *
-   * @param $source_id_values
-   *   The source identifier values of the record.
-   */
-  public function setUpdate(array $source_id_values);
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigratePluginManager.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/MigratePluginManager.php
deleted file mode 100644
index a67b86e..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigratePluginManager.php
+++ /dev/null
@@ -1,60 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\MigraterPluginManager.
- */
-
-namespace Drupal\migrate\Plugin;
-
-use Drupal\Component\Plugin\Factory\DefaultFactory;
-use Drupal\Core\Cache\CacheBackendInterface;
-use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\Core\Language\LanguageManager;
-use Drupal\Core\Plugin\DefaultPluginManager;
-use Drupal\migrate\Entity\MigrationInterface;
-
-/**
- * Manages migrate sources and steps.
- *
- * @see hook_migrate_info_alter()
- */
-class MigratePluginManager extends DefaultPluginManager {
-
-  /**
-   * Constructs a MigraterPluginManager object.
-   *
-   * @param string $type
-   *   The type of the plugin: row, source, process, destination, entity_field, id_map.
-   * @param \Traversable $namespaces
-   *   An object that implements \Traversable which contains the root paths
-   *   keyed by the corresponding namespace to look for plugin implementations.
-   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
-   *   Cache backend instance to use.
-   * @param \Drupal\Core\Language\LanguageManager $language_manager
-   *   The language manager.
-   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
-   *   The module handler to invoke the alter hook with.
-   */
-  public function __construct($type, \Traversable $namespaces, CacheBackendInterface $cache_backend, LanguageManager $language_manager, ModuleHandlerInterface $module_handler) {
-    parent::__construct("Plugin/migrate/$type", $namespaces, 'Drupal\Component\Annotation\PluginID');
-    $this->alterInfo($module_handler, 'migrate_' . $type . '_info');
-    $this->setCacheBackend($cache_backend, $language_manager, 'migrate_plugins_' . $type);
-  }
-
-  /**
-   * {@inheritdoc}
-   *
-   * A specific createInstance method is necessary to pass the migration on.
-   */
-  public function createInstance($plugin_id, array $configuration = array(), MigrationInterface $migration = NULL) {
-    $plugin_definition = $this->discovery->getDefinition($plugin_id);
-    $plugin_class = DefaultFactory::getPluginClass($plugin_id, $plugin_definition);
-    // If the plugin provides a factory method, pass the container to it.
-    if (is_subclass_of($plugin_class, 'Drupal\Core\Plugin\ContainerFactoryPluginInterface')) {
-      return $plugin_class::create(\Drupal::getContainer(), $configuration, $plugin_id, $plugin_definition, $migration);
-    }
-    return new $plugin_class($configuration, $plugin_id, $plugin_definition, $migration);
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateProcessInterface.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateProcessInterface.php
deleted file mode 100644
index 74da652..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateProcessInterface.php
+++ /dev/null
@@ -1,36 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\MigrateProcessInterface.
- */
-
-namespace Drupal\migrate\Plugin;
-
-use Drupal\Component\Plugin\PluginInspectionInterface;
-use Drupal\migrate\MigrateExecutable;
-use Drupal\migrate\Row;
-
-/**
- * An interface for migrate processes.
- */
-interface MigrateProcessInterface extends PluginInspectionInterface {
-
-  /**
-   * Performs the associated process.
-   *
-   * @param $value
-   *   The value to be transformed.
-   * @param \Drupal\migrate\MigrateExecutable $migrate_executable
-   *   The migration in which this process is being executed.
-   * @param \Drupal\migrate\Row $row
-   *   The row from the source to process. Normally, just transforming the
-   *   value is adequate but very rarely you might need to change two columns
-   *   at the same time or something like that.
-   * @param string $destination_property
-   *   The destination property currently worked on. This is only used
-   *   together with the $row above.
-   */
-  public function transform($value, MigrateExecutable $migrate_executable, Row $row, $destination_property);
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateSourceInterface.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateSourceInterface.php
deleted file mode 100644
index 9b9b982..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/MigrateSourceInterface.php
+++ /dev/null
@@ -1,45 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\MigrateSourceInterface.
- */
-
-namespace Drupal\migrate\Plugin;
-use Drupal\Component\Plugin\PluginInspectionInterface;
-use Drupal\migrate\Row;
-
-/**
- * Defines an interface for migrate sources.
- */
-interface MigrateSourceInterface extends \Countable, PluginInspectionInterface {
-
-  /**
-   * Returns available fields on the source.
-   *
-   * @return array
-   *   Available fields in the source, keys are the field machine names as used
-   *   in field mappings, values are descriptions.
-   */
-  public function fields();
-
-
-  /**
-   * Returns the iterator that will yield the row arrays to be processed.
-   *
-   * @return \Iterator
-   */
-  public function getIterator();
-
-  /**
-   * Add additional data to the row.
-   *
-   * @param \Drupal\Migrate\Row $row
-   *
-   * @return bool
-   *   FALSE if this row needs to be skipped.
-   */
-  public function prepareRow(Row $row);
-
-  public function __toString();
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/RequirementsInterface.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/RequirementsInterface.php
deleted file mode 100644
index ad45be5..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/RequirementsInterface.php
+++ /dev/null
@@ -1,23 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\RequirementsInterface.
- */
-
-namespace Drupal\migrate\Plugin;
-
-/**
- * An interface to check for a migrate plugin requirements.
- */
-interface RequirementsInterface {
-
-  /**
-   * Checks if requirements for this plugin are OK.
-   *
-   * @return boolean
-   *   TRUE if it is possible to use the plugin, FALSE if not.
-   */
-  public function checkRequirements();
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/destination/Config.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/destination/Config.php
deleted file mode 100644
index 36ead84..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/destination/Config.php
+++ /dev/null
@@ -1,87 +0,0 @@
-<?php
-/**
- * @file
- *   Provides Configuration Management destination plugin.
- */
-
-namespace Drupal\migrate\Plugin\migrate\destination;
-
-use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
-use Drupal\migrate\Entity\Migration;
-use Drupal\migrate\MigrateException;
-use Drupal\migrate\Row;
-use Symfony\Component\DependencyInjection\ContainerInterface;
-use Drupal\Core\Config\Config as ConfigObject;
-
-/**
- * Persist data to the config system.
- *
- * @PluginID("d8_config")
- */
-class Config extends DestinationBase implements ContainerFactoryPluginInterface {
-
-  /**
-   * The config object.
-   *
-   * @var \Drupal\Core\Config\Config
-   */
-  protected $config;
-
-  /**
-   * @param array $configuration
-   * @param string $plugin_id
-   * @param array $plugin_definition
-   * @param ConfigObject $config
-   */
-  public function __construct(array $configuration, $plugin_id, array $plugin_definition, ConfigObject $config) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition);
-    $this->config = $config;
-  }
-
-  public static function create(ContainerInterface $container, array $configuration, $plugin_id, array $plugin_definition) {
-    return new static(
-      $configuration,
-      $plugin_id,
-      $plugin_definition,
-      $container->get('config.factory')->get($configuration['config_name'])
-    );
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function import(Row $row) {
-    $this->config
-      ->setData($row->getDestination())
-      ->save();
-  }
-
-  /**
-   * @param array $destination_keys
-   *
-   * @throws \Drupal\migrate\MigrateException
-   */
-  public function rollbackMultiple(array $destination_keys) {
-    throw new MigrateException('Configuration can not be rolled back');
-  }
-
-  /**
-   * Derived classes must implement fields(), returning a list of available
-   * destination fields.
-   *
-   * @todo Review the cases where we need the Migration parameter, can we avoid that?
-   *
-   * @param Migration $migration
-   *   Optionally, the migration containing this destination.
-   * @return array
-   *  - Keys: machine names of the fields
-   *  - Values: Human-friendly descriptions of the fields.
-   */
-  public function fields(Migration $migration = NULL) {
-    // @todo Dynamically fetch fields using Config Schema API.
-  }
-
-  public function getIdsSchema() {
-    return array($this->config->getName() => array());
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/destination/DestinationBase.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/destination/DestinationBase.php
deleted file mode 100644
index 7cdf11b..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/destination/DestinationBase.php
+++ /dev/null
@@ -1,53 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\destination\DestinationBase.
- */
-
-
-namespace Drupal\migrate\Plugin\migrate\destination;
-
-use Drupal\Core\Plugin\PluginBase;
-use Drupal\migrate\Plugin\MigrateDestinationInterface;
-
-abstract class DestinationBase extends PluginBase implements MigrateDestinationInterface {
-
-  /**
-   * Modify the Row before it is imported.
-   */
-  public function preImport() {
-    // TODO: Implement preImport() method.
-  }
-
-  /**
-   * Modify the Row before it is rolled back.
-   */
-  public function preRollback() {
-    // TODO: Implement preRollback() method.
-  }
-
-  public function postImport() {
-    // TODO: Implement postImport() method.
-  }
-
-  public function postRollback() {
-    // TODO: Implement postRollback() method.
-  }
-
-  public function rollbackMultiple(array $destination_identifiers) {
-    // TODO: Implement rollbackMultiple() method.
-  }
-
-  public function getCreated() {
-    // TODO: Implement getCreated() method.
-  }
-
-  public function getUpdated() {
-    // TODO: Implement getUpdated() method.
-  }
-
-  public function resetStats() {
-    // TODO: Implement resetStats() method.
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/id_map/Sql.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/id_map/Sql.php
deleted file mode 100644
index 02ad801..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/id_map/Sql.php
+++ /dev/null
@@ -1,705 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\id_map\Sql.
- */
-
-namespace Drupal\migrate\Plugin\migrate\id_map;
-
-use Drupal\Component\Utility\Unicode;
-use Drupal\Core\Plugin\PluginBase;
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\MigrateException;
-use Drupal\migrate\MigrateMessageInterface;
-use Drupal\migrate\Plugin\migrate\source\SqlBase;
-use Drupal\migrate\Plugin\MigrateIdMapInterface;
-use Drupal\migrate\Row;
-
-/**
- * Defines the sql based ID map implementation.
- *
- * It creates one map and one message table per migration entity to store the
- * relevant information.
- *
- * @PluginID("sql")
- */
-class Sql extends PluginBase implements MigrateIdMapInterface {
-
-  /**
-   * Names of tables created for tracking the migration.
-   *
-   * @var string
-   */
-  protected $mapTable, $messageTable;
-
-  /**
-   * The migrate message.
-   *
-   * @var \Drupal\migrate\MigrateMessageInterface
-   */
-  protected $message;
-
-  /**
-   * The database connection for the map/message tables on the destination.
-   *
-   * @var \Drupal\Core\Database\Connection
-   */
-  protected $database;
-
-  /**
-   * @var \Drupal\Core\Database\Query\SelectInterface
-   */
-  protected $query;
-
-  /**
-   * The migration being done.
-   *
-   * @var \Drupal\migrate\Entity\MigrationInterface
-   */
-  protected $migration;
-
-  /**
-   * The source ID fields.
-   *
-   * @var array
-   */
-  protected $sourceIdFields;
-
-  /**
-   * The destination ID fields.
-   *
-   * @var array
-   */
-  protected $destinationIdFields;
-
-  /**
-   * Stores whether the the tables (map/message) already exist.
-   *
-   * This is determined just once per request/instance of the class.
-   *
-   * @var boolean
-   */
-  protected $ensured;
-
-  /**
-   * The result.
-   *
-   * @var null
-   */
-  protected $result = NULL;
-
-  /**
-   * The current row.
-   *
-   * @var null
-   */
-  protected $currentRow = NULL;
-
-  /**
-   * The current key.
-   *
-   * @var array
-   */
-  protected $currentKey = array();
-
-  /**
-   * Constructs an SQL object.
-   *
-   * Sets up the tables and builds the maps,
-   *
-   * @param array $configuration
-   *   The configuration.
-   * @param string $plugin_id
-   *   The plugin ID for the migration process to do.
-   * @param array $plugin_definition
-   *   The configuration for the plugin.
-   * @param \Drupal\migrate\Entity\MigrationInterface $migration
-   *   The migration to do.
-   */
-  public function __construct(array $configuration, $plugin_id, array $plugin_definition, MigrationInterface $migration) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition);
-
-    $this->migration = $migration;
-    $machine_name = $migration->id();
-
-    // Default generated table names, limited to 63 characters.
-    $prefixLength = strlen($this->getDatabase()->tablePrefix()) ;
-    $this->mapTable = 'migrate_map_' . Unicode::strtolower($machine_name);
-    $this->mapTable = Unicode::substr($this->mapTable, 0, 63 - $prefixLength);
-    $this->messageTable = 'migrate_message_' . Unicode::strtolower($machine_name);
-    $this->messageTable = Unicode::substr($this->messageTable, 0, 63 - $prefixLength);
-    $this->sourceIds = $migration->get('sourceIds');
-    $this->destinationIds = $migration->get('destinationIds');
-
-    // Build the source and destination identifier maps.
-    $this->sourceIdFields = array();
-    $count = 1;
-    foreach ($this->sourceIds as $field => $schema) {
-      $this->sourceIdFields[$field] = 'sourceid' . $count++;
-    }
-    $this->destinationIdFields = array();
-    $count = 1;
-    foreach ($this->destinationIds as $field => $schema) {
-      $this->destinationIdFields[$field] = 'destid' . $count++;
-    }
-    $this->ensureTables();
-  }
-
-  /**
-   * Qualifying the map table name with the database name makes cross-db joins
-   * possible. Note that, because prefixes are applied after we do this (i.e.,
-   * it will prefix the string we return), we do not qualify the table if it has
-   * a prefix. This will work fine when the source data is in the default
-   * (prefixed) database (in particular, for simpletest), but not if the primary
-   * query is in an external database.
-   *
-   * @return string
-   */
-  public function getQualifiedMapTable() {
-    $options = $this->getDatabase()->getConnectionOptions();
-    $prefix = $this->getDatabase()->tablePrefix($this->mapTable);
-    if ($prefix) {
-      return $this->mapTable;
-    }
-    else {
-      return $options['database'] . '.' . $this->mapTable;
-    }
-  }
-
-  /**
-   * Gets the database connection.
-   *
-   * @return \Drupal\Core\Database\Connection
-   */
-  protected function getDatabase() {
-    if (!isset($this->database)) {
-      $this->database = SqlBase::getDatabaseConnection($this->migration->id(), $this->configuration);
-    }
-    return $this->database;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setMessage(MigrateMessageInterface $message) {
-    $this->message = $message;
-  }
-
-  /**
-   * Create the map and message tables if they don't already exist.
-   */
-  protected function ensureTables() {
-    if (!$this->ensured) {
-      if (!$this->getDatabase()->schema()->tableExists($this->mapTable)) {
-        // Generate appropriate schema info for the map and message tables,
-        // and map from the source field names to the map/msg field names.
-        $count = 1;
-        $source_id_schema = array();
-        $pks = array();
-        foreach ($this->sourceIds as $field_schema) {
-          $mapkey = 'sourceid' . $count++;
-          $source_id_schema[$mapkey] = $field_schema;
-          $pks[] = $mapkey;
-        }
-
-        $fields = $source_id_schema;
-
-        // Add destination identifiers to map table.
-        // TODO: How do we discover the destination schema?
-        $count = 1;
-        foreach ($this->destinationIds as $field_schema) {
-          // Allow dest identifier fields to be NULL (for IGNORED/FAILED
-          // cases).
-          $field_schema['not null'] = FALSE;
-          $mapkey = 'destid' . $count++;
-          $fields[$mapkey] = $field_schema;
-        }
-        $fields['needs_update'] = array(
-          'type' => 'int',
-          'size' => 'tiny',
-          'unsigned' => TRUE,
-          'not null' => TRUE,
-          'default' => MigrateIdMapInterface::STATUS_IMPORTED,
-          'description' => 'Indicates current status of the source row',
-        );
-        $fields['rollback_action'] = array(
-          'type' => 'int',
-          'size' => 'tiny',
-          'unsigned' => TRUE,
-          'not null' => TRUE,
-          'default' => MigrateIdMapInterface::ROLLBACK_DELETE,
-          'description' => 'Flag indicating what to do for this item on rollback',
-        );
-        $fields['last_imported'] = array(
-          'type' => 'int',
-          'unsigned' => TRUE,
-          'not null' => TRUE,
-          'default' => 0,
-          'description' => 'UNIX timestamp of the last time this row was imported',
-        );
-        $fields['hash'] = array(
-          'type' => 'varchar',
-          'length' => '32',
-          'not null' => FALSE,
-          'description' => 'Hash of source row data, for detecting changes',
-        );
-        $schema = array(
-          'description' => 'Mappings from source identifier value(s) to destination identifier value(s).',
-          'fields' => $fields,
-        );
-        if ($pks) {
-          $schema['primary key'] = $pks;
-        }
-        $this->getDatabase()->schema()->createTable($this->mapTable, $schema);
-
-        // Now do the message table.
-        $fields = array();
-        $fields['msgid'] = array(
-          'type' => 'serial',
-          'unsigned' => TRUE,
-          'not null' => TRUE,
-        );
-        $fields += $source_id_schema;
-
-        $fields['level'] = array(
-          'type' => 'int',
-          'unsigned' => TRUE,
-          'not null' => TRUE,
-          'default' => 1,
-        );
-        $fields['message'] = array(
-          'type' => 'text',
-          'size' => 'medium',
-          'not null' => TRUE,
-        );
-        $schema = array(
-          'description' => 'Messages generated during a migration process',
-          'fields' => $fields,
-          'primary key' => array('msgid'),
-        );
-        if ($pks) {
-          $schema['indexes']['sourcekey'] = $pks;
-        }
-        $this->getDatabase()->schema()->createTable($this->messageTable, $schema);
-      }
-      else {
-        // Add any missing columns to the map table.
-        if (!$this->getDatabase()->schema()->fieldExists($this->mapTable,
-                                                      'rollback_action')) {
-          $this->getDatabase()->schema()->addField($this->mapTable,
-                                                'rollback_action', array(
-            'type' => 'int',
-            'size' => 'tiny',
-            'unsigned' => TRUE,
-            'not null' => TRUE,
-            'default' => 0,
-            'description' => 'Flag indicating what to do for this item on rollback',
-          ));
-        }
-        if (!$this->getDatabase()->schema()->fieldExists($this->mapTable, 'hash')) {
-          $this->getDatabase()->schema()->addField($this->mapTable, 'hash', array(
-            'type' => 'varchar',
-            'length' => '32',
-            'not null' => FALSE,
-            'description' => 'Hash of source row data, for detecting changes',
-          ));
-        }
-      }
-      $this->ensured = TRUE;
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getRowBySource(array $source_id_value) {
-    $query = $this->getDatabase()->select($this->mapTable, 'map')
-              ->fields('map');
-    foreach ($this->sourceIdFields as $source_id) {
-      $query = $query->condition("map.$source_id", array_shift($source_id_value), '=');
-    }
-    $result = $query->execute();
-    return $result->fetchAssoc();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getRowByDestination(array $destination_id_values) {
-    $query = $this->getDatabase()->select($this->mapTable, 'map')
-              ->fields('map');
-    foreach ($this->destinationIdFields as $destination_id) {
-      $query = $query->condition("map.$destination_id", array_shift($destination_id_values), '=');
-    }
-    $result = $query->execute();
-    return $result->fetchAssoc();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getRowsNeedingUpdate($count) {
-    $rows = array();
-    $result = $this->getDatabase()->select($this->mapTable, 'map')
-                      ->fields('map')
-                      ->condition('needs_update', MigrateIdMapInterface::STATUS_NEEDS_UPDATE)
-                      ->range(0, $count)
-                      ->execute();
-    foreach ($result as $row) {
-      $rows[] = $row;
-    }
-    return $rows;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function lookupSourceID(array $destination_id) {
-    $query = $this->getDatabase()->select($this->mapTable, 'map')
-              ->fields('map', $this->sourceIdFields);
-    foreach ($this->destinationIdFields as $key_name) {
-      $query = $query->condition("map.$key_name", array_shift($destination_id), '=');
-    }
-    $result = $query->execute();
-    $source_id = $result->fetchAssoc();
-    return $source_id;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function lookupDestinationID(array $source_id) {
-    $query = $this->getDatabase()->select($this->mapTable, 'map')
-              ->fields('map', $this->destinationIdFields);
-    foreach ($this->sourceIdFields as $key_name) {
-      $query = $query->condition("map.$key_name", array_shift($source_id), '=');
-    }
-    $result = $query->execute();
-    $destination_id = $result->fetchAssoc();
-    return $destination_id;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function saveIdMapping(Row $row, array $destination_id_values, $needs_update = MigrateIdMapInterface::STATUS_IMPORTED, $rollback_action = MigrateIdMapInterface::ROLLBACK_DELETE) {
-    // Construct the source key.
-    $source_id_values = $row->getSourceIdValues();
-    // Construct the source key and initialize to empty variable keys.
-    $keys = array();
-    foreach ($this->sourceIdFields as $field_name => $key_name) {
-      // A NULL key value will fail.
-      if (!isset($source_id_values[$field_name])) {
-        $this->message->display(t(
-          'Could not save to map table due to NULL value for key field !field',
-          array('!field' => $field_name)));
-        return;
-      }
-      $keys[$key_name] = $source_id_values[$field_name];
-    }
-
-    $fields = array(
-      'needs_update' => (int) $needs_update,
-      'rollback_action' => (int) $rollback_action,
-      'hash' => $row->getHash(),
-    );
-    $count = 1;
-    foreach ($destination_id_values as $dest_id) {
-      $fields['destid' . $count++] = $dest_id;
-    }
-    if ($this->migration->get('trackLastImported')) {
-      $fields['last_imported'] = time();
-    }
-    if ($keys) {
-      $this->getDatabase()->merge($this->mapTable)
-        ->key($keys)
-        ->fields($fields)
-        ->execute();
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function saveMessage(array $source_id_values, $message, $level = MigrationInterface::MESSAGE_ERROR) {
-    $count = 1;
-    foreach ($source_id_values as $id_value) {
-      $fields['sourceid' . $count++] = $id_value;
-      // If any key value is empty, we can't save - print out and abort.
-      if (empty($id_value)) {
-        print($message);
-        return;
-      }
-    }
-    $fields['level'] = $level;
-    $fields['message'] = $message;
-    $this->getDatabase()->insert($this->messageTable)
-      ->fields($fields)
-      ->execute();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function prepareUpdate() {
-    $this->getDatabase()->update($this->mapTable)
-    ->fields(array('needs_update' => MigrateIdMapInterface::STATUS_NEEDS_UPDATE))
-    ->execute();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function processedCount() {
-    return $this->getDatabase()->select($this->mapTable)
-      ->countQuery()
-      ->execute()
-      ->fetchField();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function importedCount() {
-    return $this->getDatabase()->select($this->mapTable)
-      ->condition('needs_update', array(MigrateIdMapInterface::STATUS_IMPORTED, MigrateIdMapInterface::STATUS_NEEDS_UPDATE), 'IN')
-      ->countQuery()
-      ->execute()
-      ->fetchField();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function updateCount() {
-    return $this->countHelper(MigrateIdMapInterface::STATUS_NEEDS_UPDATE);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function errorCount() {
-    return $this->countHelper(MigrateIdMapInterface::STATUS_FAILED);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function messageCount() {
-    return $this->countHelper(NULL, $this->messageTable);
-  }
-
-  /**
-   * Counts records in a table.
-   *
-   * @param $status
-   *   An integer for the needs_update column.
-   * @param $table
-   *   The table to work
-   * @return int
-   *   The number of records.
-   */
-  protected function countHelper($status, $table = NULL) {
-    $query = $this->getDatabase()->select($table ?: $this->mapTable);
-    if (isset($status)) {
-      $query->condition('needs_update', $status);
-    }
-    return $query->countQuery()->execute()->fetchField();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function delete(array $source_id_values, $messages_only = FALSE) {
-    if (empty($source_id_values)) {
-      throw new MigrateException('Without source identifier values it is impossible to find the row to delete.');
-    }
-    if (!$messages_only) {
-      $map_query = $this->getDatabase()->delete($this->mapTable);
-    }
-    $message_query = $this->getDatabase()->delete($this->messageTable);
-    $count = 1;
-    foreach ($source_id_values as $id_value) {
-      if (!$messages_only) {
-        $map_query->condition('sourceid' . $count, $id_value);
-      }
-      $message_query->condition('sourceid' . $count, $id_value);
-      $count++;
-    }
-
-    if (!$messages_only) {
-      $map_query->execute();
-    }
-    $message_query->execute();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function deleteDestination(array $destination_id) {
-    $map_query = $this->getDatabase()->delete($this->mapTable);
-    $message_query = $this->getDatabase()->delete($this->messageTable);
-    $source_id = $this->lookupSourceID($destination_id);
-    if (!empty($source_id)) {
-      $count = 1;
-      foreach ($destination_id as $key_value) {
-        $map_query->condition('destid' . $count, $key_value);
-        $count++;
-      }
-      $map_query->execute();
-      $count = 1;
-      foreach ($source_id as $key_value) {
-        $message_query->condition('sourceid' . $count, $key_value);
-        $count++;
-      }
-      $message_query->execute();
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setUpdate(array $source_id) {
-    if (empty($source_ids)) {
-      throw new MigrateException('No source identifiers provided to update.');
-    }
-    $query = $this->getDatabase()
-      ->update($this->mapTable)
-      ->fields(array('needs_update' => MigrateIdMapInterface::STATUS_NEEDS_UPDATE));
-    $count = 1;
-    foreach ($source_id as $key_value) {
-      $query->condition('sourceid' . $count++, $key_value);
-    }
-    $query->execute();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function deleteBulk(array $source_id_values) {
-    // If we have a single-column key, we can shortcut it.
-    if (count($this->sourceIds) == 1) {
-      $sourceids = array();
-      foreach ($source_id_values as $source_id) {
-        $sourceids[] = $source_id;
-      }
-      $this->getDatabase()->delete($this->mapTable)
-        ->condition('sourceid1', $sourceids, 'IN')
-        ->execute();
-      $this->getDatabase()->delete($this->messageTable)
-        ->condition('sourceid1', $sourceids, 'IN')
-        ->execute();
-    }
-    else {
-      foreach ($source_id_values as $source_id) {
-        $map_query = $this->getDatabase()->delete($this->mapTable);
-        $message_query = $this->getDatabase()->delete($this->messageTable);
-        $count = 1;
-        foreach ($source_id as $key_value) {
-          $map_query->condition('sourceid' . $count, $key_value);
-          $message_query->condition('sourceid' . $count++, $key_value);
-        }
-        $map_query->execute();
-        $message_query->execute();
-      }
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function clearMessages() {
-    $this->getDatabase()->truncate($this->messageTable)->execute();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function destroy() {
-    $this->getDatabase()->schema()->dropTable($this->mapTable);
-    $this->getDatabase()->schema()->dropTable($this->messageTable);
-  }
-
-  /**
-   * Implementation of Iterator::rewind().
-   *
-   * This is called before beginning a foreach loop.
-   *
-   * @todo Support idlist, itemlimit.
-   */
-  public function rewind() {
-    $this->currentRow = NULL;
-    $fields = array();
-    foreach ($this->sourceIdFields as $field) {
-      $fields[] = $field;
-    }
-    foreach ($this->destinationIdFields as $field) {
-      $fields[] = $field;
-    }
-
-    // @todo Make this work.
-    /*
-    if (isset($this->options['itemlimit'])) {
-      $query = $query->range(0, $this->options['itemlimit']);
-    }
-    */
-    $this->result = $this->getDatabase()->select($this->mapTable, 'map')
-      ->fields('map', $fields)
-      ->execute();
-    $this->next();
-  }
-
-  /**
-   * Implementation of Iterator::current().
-   *
-   * This is called when entering a loop iteration, returning the current row.
-   */
-  public function current() {
-    return $this->currentRow;
-  }
-
-  /**
-   * Implementation of Iterator::key().
-   *
-   * This is called when entering a loop iteration, returning the key of the
-   * current row. It must be a scalar - we will serialize to fulfill the
-   * requirement, but using getCurrentKey() is preferable.
-   */
-  public function key() {
-    return serialize($this->currentKey);
-  }
-
-  /**
-   * Implementation of Iterator::next().
-   *
-   * This is called at the bottom of the loop implicitly, as well as explicitly
-   * from rewind().
-   */
-  public function next() {
-    $this->currentRow = $this->result->fetchObject();
-    $this->currentKey = array();
-    if (!is_object($this->currentRow)) {
-      $this->currentRow = NULL;
-    }
-    else {
-      foreach ($this->sourceIdFields as $map_field) {
-        $this->currentKey[$map_field] = $this->currentRow->$map_field;
-        // Leave only destination fields.
-        unset($this->currentRow->$map_field);
-      }
-    }
-  }
-
-  /**
-   * Implementation of Iterator::valid().
-   *
-   * This is called at the top of the loop, returning TRUE to process the loop
-   * and FALSE to terminate it.
-   */
-  public function valid() {
-    // @todo Check numProcessed against itemlimit.
-    return !is_null($this->currentRow);
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/process/DefaultValue.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/process/DefaultValue.php
deleted file mode 100644
index 580eed8..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/process/DefaultValue.php
+++ /dev/null
@@ -1,29 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\process\DefaultValue.
- */
-
-namespace Drupal\migrate\Plugin\migrate\process;
-
-use Drupal\Core\Plugin\PluginBase;
-use Drupal\migrate\MigrateExecutable;
-use Drupal\migrate\Plugin\MigrateProcessInterface;
-use Drupal\migrate\Row;
-
-
-/**
- * This plugin sets missing values on the destination.
- *
- * @PluginId("default_value")
- */
-class DefaultValue extends PluginBase implements MigrateProcessInterface {
-
- /**
-   * {@inheritdoc}
-   */
-  public function transform($value, MigrateExecutable $migrate_executable, Row $row, $destination_property) {
-    return isset($value) ? $value : $this->configuration['default_value'];
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/process/Get.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/process/Get.php
deleted file mode 100644
index 6f2f51e..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/process/Get.php
+++ /dev/null
@@ -1,55 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\process\CopyFromSource.
- */
-
-namespace Drupal\migrate\Plugin\migrate\process;
-
-use Drupal\Core\Plugin\PluginBase;
-use Drupal\migrate\MigrateExecutable;
-use Drupal\migrate\Plugin\MigrateProcessInterface;
-use Drupal\migrate\Row;
-
-/**
- * This plugin copies from the source to the destination.
- *
- * @PluginId("get")
- */
-class Get extends PluginBase implements MigrateProcessInterface {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function transform($value, MigrateExecutable $migrate_executable, Row $row, $destination_property) {
-    $source = $this->configuration['source'];
-    $properties = is_string($source) ? array($source) : $source;
-    $return = array();
-    foreach ($properties as $property) {
-      if (empty($property)) {
-        $return[] = $value;
-      }
-      else {
-        $is_source = TRUE;
-        if ($property[0] == '@') {
-          $property = preg_replace_callback('/^(@?)((?:@@)*)([^@]|$)/', function ($matches) use (&$is_source) {
-            // If there are an odd number of @ in the beginning, it's a
-            // destination.
-            $is_source = empty($matches[1]);
-            // Remove the possible escaping and do not lose the terminating
-            // non-@ either.
-            return str_replace('@@', '@', $matches[2]) . $matches[3];
-          }, $property);
-        }
-        if ($is_source) {
-          $return[] = $row->getSourceProperty($property);
-        }
-        else {
-          $return[] = $row->getDestinationProperty($property);
-        }
-      }
-    }
-    return is_string($source) ? $return[0] : $return;
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/D6Variable.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/D6Variable.php
deleted file mode 100644
index 3160d53..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/D6Variable.php
+++ /dev/null
@@ -1,59 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\source\d6\Variable.
- */
-
-namespace Drupal\migrate\Plugin\migrate\source;
-
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\Plugin\migrate\source\d6\Drupal6SqlBase;
-
-/**
- * Drupal 6 variable source from database.
- *
- * @PluginID("drupal6_variable")
- */
-class D6Variable extends Drupal6SqlBase {
-
-  /**
-   * The variable names to fetch.
-   *
-   * @var array
-   */
-  protected $variables;
-
-  /**
-   * {@inheritdoc}
-   */
-  function __construct(array $configuration, $plugin_id, array $plugin_definition, MigrationInterface $migration) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration);
-    $this->variables = $this->configuration['variables'];
-  }
-
-  protected function runQuery() {
-    return new \ArrayIterator(array(array_map('unserialize', $this->query()->execute()->fetchAllKeyed())));
-  }
-
-  public function count() {
-    return intval($this->query()->countQuery()->execute()->fetchField() > 0);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function fields() {
-    return drupal_map_assoc($this->variables);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  function query() {
-    return $this->getDatabase()
-      ->select('variable', 'v')
-      ->fields('v', array('name', 'value'))
-      ->condition('name', $this->variables, 'IN');
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/SourcePluginBase.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/SourcePluginBase.php
deleted file mode 100644
index 78eb2fa..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/SourcePluginBase.php
+++ /dev/null
@@ -1,54 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\source\SourcePluginBase.
- */
-
-namespace Drupal\migrate\Plugin\migrate\source;
-
-use Drupal\Core\Plugin\PluginBase;
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\Plugin\MigrateSourceInterface;
-use Drupal\migrate\Row;
-
-abstract class SourcePluginBase extends PluginBase implements MigrateSourceInterface  {
-
-  /**
-   * @var \Drupal\Core\Extension\ModuleHandlerInterface
-   */
-  protected $moduleHandler;
-
-  /**
-   * @var \Drupal\migrate\Entity\MigrationInterface
-   */
-  protected $migration;
-
-  /**
-   * {@inheritdoc}
-   */
-  function __construct(array $configuration, $plugin_id, array $plugin_definition, MigrationInterface $migration) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition);
-    $this->migration = $migration;
-  }
-
-   /**
-   * @return \Drupal\Core\Extension\ModuleHandlerInterface
-   */
-  protected function getModuleHandler() {
-    if (!isset($this->moduleHandler)) {
-      $this->moduleHandler = \Drupal::moduleHandler();
-    }
-    return $this->moduleHandler;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function prepareRow(Row $row) {
-    $this->getModuleHandler()->invokeAll('migrate_prepare_row', $row, $this, $this->migration);
-    $this->getModuleHandler()->invokeAll('migrate_ '. $this->migration->id() . '_prepare_row', $row, $this, $this->migration);
-    return TRUE;
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/SqlBase.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/SqlBase.php
deleted file mode 100644
index 9a17436..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/SqlBase.php
+++ /dev/null
@@ -1,192 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\source\SqlBase.
- */
-
-namespace Drupal\migrate\Plugin\migrate\source;
-
-use Drupal\Core\Database\Database;
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\Plugin\MigrateIdMapInterface;
-
-/**
- * Sources whose data may be fetched via DBTNG.
- */
-abstract class SqlBase extends SourcePluginBase {
-
-  /**
-   * @var \Drupal\Core\Database\Query\SelectInterface
-   */
-  protected $query;
-
-  /**
-   * @var \Drupal\migrate\Entity\MigrationInterface
-   */
-  protected $migration;
-
-  /**
-   * @var \Drupal\Core\Database\Connection
-   */
-  protected $database;
-
-  /**
-   * {@inheritdoc}
-   */
-  function __construct(array $configuration, $plugin_id, array $plugin_definition, MigrationInterface $migration) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration);
-    $this->mapJoinable = TRUE;
-  }
-
-  /**
-   * @return \Drupal\Core\Database\Connection
-   */
-  function __toString() {
-    return (string) $this->query;
-  }
-
-  /**
-   * @return \Drupal\Core\Database\Connection
-   */
-  public function getDatabase() {
-    if  (!isset($this->database)) {
-      $this->database = static::getDatabaseConnection($this->migration->id(), $this->configuration);
-    }
-    return $this->database;
-  }
-
-  public static function getDatabaseConnection($id, array $configuration) {
-    if (isset($configuration['database'])) {
-      $key = 'migrate_' . $id;
-      Database::addConnectionInfo($key, 'default', $configuration['database']);
-    }
-    else {
-      $key = 'default';
-    }
-    return Database::getConnection('default', $key);
-  }
-
-  protected function select($table, $alias = NULL, array $options = array()) {
-    $options['fetch'] = \PDO::FETCH_ASSOC;
-    return $this->getDatabase()->select($table, $alias, $options);
-  }
-
-  /**
-   * Implementation of MigrateSource::performRewind().
-   *
-   * We could simply execute the query and be functionally correct, but
-   * we will take advantage of the PDO-based API to optimize the query up-front.
-   */
-  protected function runQuery() {
-    $this->query = clone $this->query();
-    $this->query->addTag('migrate');
-    $this->query->addTag('migrate_' . $this->migration->id());
-    $this->query->addMetaData('migration', $this->migration);
-    $highwaterProperty = $this->migration->get('highwaterProperty');
-
-    // Get the key values, for potential use in joining to the map table, or
-    // enforcing idlist.
-    $keys = array();
-    foreach ($this->migration->get('sourceIds') as $field_name => $field_schema) {
-      if (isset($field_schema['alias'])) {
-        $field_name = $field_schema['alias'] . '.' . $field_name;
-      }
-      $keys[] = $field_name;
-    }
-
-    // The rules for determining what conditions to add to the query are as
-    // follows (applying first applicable rule)
-    // 1. If idlist is provided, then only process items in that list (AND key
-    //    IN (idlist)). Only applicable with single-value keys.
-    if ($id_list = $this->migration->get('idlist')) {
-      $this->query->condition($keys[0], $id_list, 'IN');
-    }
-    else {
-      // 2. If the map is joinable, join it. We will want to accept all rows
-      //    which are either not in the map, or marked in the map as NEEDS_UPDATE.
-      //    Note that if highwater fields are in play, we want to accept all rows
-      //    above the highwater mark in addition to those selected by the map
-      //    conditions, so we need to OR them together (but AND with any existing
-      //    conditions in the query). So, ultimately the SQL condition will look
-      //    like (original conditions) AND (map IS NULL OR map needs update
-      //      OR above highwater).
-      $conditions = $this->query->orConditionGroup();
-      $condition_added = FALSE;
-      if ($this->mapJoinable) {
-        // Build the join to the map table. Because the source key could have
-        // multiple fields, we need to build things up.
-        $count = 1;
-        $map_join = '';
-        $delimiter = '';
-        foreach ($this->migration->get('sourceIds') as $field_name => $field_schema) {
-          if (isset($field_schema['alias'])) {
-            $field_name = $field_schema['alias'] . '.' . $field_name;
-          }
-          $map_join .= "$delimiter$field_name = map.sourceid" . $count++;
-          $delimiter = ' AND ';
-        }
-
-        $alias = $this->query->leftJoin($this->migration->getIdMap()->getQualifiedMapTable(), 'map', $map_join);
-        $conditions->isNull($alias . '.sourceid1');
-        $conditions->condition($alias . '.needs_update', MigrateIdMapInterface::STATUS_NEEDS_UPDATE);
-        $condition_added = TRUE;
-
-        // And as long as we have the map table, add its data to the row.
-        $n = count($this->migration->get('sourceIds'));
-        for ($count = 1; $count <= $n; $count++) {
-          $map_key = 'sourceid' . $count;
-          $this->query->addField($alias, $map_key, "migrate_map_$map_key");
-        }
-        $n = count($this->migration->get('destinationIds'));
-        for ($count = 1; $count <= $n; $count++) {
-          $map_key = 'destid' . $count++;
-          $this->query->addField($alias, $map_key, "migrate_map_$map_key");
-        }
-        $this->query->addField($alias, 'needs_update', 'migrate_map_needs_update');
-      }
-      // 3. If we are using highwater marks, also include rows above the mark.
-      //    But, include all rows if the highwater mark is not set.
-      if (isset($highwaterProperty['name']) && ($highwater = $this->migration->getHighwater()) !== '') {
-        if (isset($highwaterProperty['alias'])) {
-          $highwater = $highwaterProperty['alias'] . '.' . $highwaterProperty['name'];
-        }
-        else {
-          $highwater = $highwaterProperty['name'];
-        }
-        $conditions->condition($highwater, $highwater, '>');
-        $condition_added = TRUE;
-      }
-      if ($condition_added) {
-        $this->query->condition($conditions);
-      }
-    }
-
-    return new \IteratorIterator($this->query->execute());
-  }
-
-  /**
-   * @return \Drupal\Core\Database\Query\SelectInterface
-   */
-  abstract function query();
-
-  /**
-   * {@inheritdoc}
-   */
-  public function count() {
-    return $this->query()->countQuery()->execute()->fetchField();
-  }
-
-  /**
-   * Returns the iterator that will yield the row arrays to be processed.
-   *
-   * @return \Iterator
-   */
-  public function getIterator() {
-    if (!isset($this->iterator)) {
-      $this->iterator = $this->runQuery();
-    }
-    return $this->iterator;
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/d6/Drupal6SqlBase.php b/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/d6/Drupal6SqlBase.php
deleted file mode 100644
index 579d87a..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Plugin/migrate/source/d6/Drupal6SqlBase.php
+++ /dev/null
@@ -1,82 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\source\d6\Drupal6SqlBase.
- */
-
-namespace Drupal\migrate\Plugin\migrate\source\d6;
-
-use Drupal\migrate\Plugin\migrate\source\SqlBase;
-
-/**
- * A base source class for Drupal 6 migrate sources.
- *
- * Mainly to let children retrieve information from the origin system in an
- * easier way.
- */
-abstract class Drupal6SqlBase extends SqlBase {
-
-  /**
-   * Retrieves all system data information from origin system.
-   *
-   * @return array
-   *   List of system table information keyed by type and name.
-   */
-  public function getSystemData() {
-    static $system_data;
-    if (isset($system_data)) {
-      return $system_data;
-    }
-    $results = $this->database
-      ->select('system', 's')
-      ->fields('s')
-      ->execute();
-    foreach ($results as $result) {
-      $system_data[$result['type']][$result['name']] = $result;
-    }
-    return $system_data;
-  }
-
-  /**
-   * Get a module schema_version value in the source installation.
-   *
-   * @param string $module
-   *   Name of module.
-   *
-   * @return mixed
-   *   The current module schema version on the origin system table or FALSE if
-   *   not found.
-   */
-  protected function getModuleSchemaVersion($module) {
-    $system_data = $this->getSystemData();
-    return isset($system_data['module'][$module]['schema_version']) ? $system_data['module'][$module]['schema_version'] : FALSE;
-  }
-
-  /**
-   * Check to see if a given module is enabled in the source installation.
-   *
-   * @param string $module
-   *   Name of module to check.
-   *
-   * @return bool
-   *   TRUE if module is enabled on the origin system, FALSE if not.
-   */
-  protected function moduleExists($module) {
-    return isset($system_data['module'][$module]['status']) ? (bool) $system_data['module'][$module]['status'] : FALSE;
-  }
-
-  protected function variableGet($name, $default) {
-    try {
-      $result = $this->database
-        ->query('SELECT value FROM {variable} WHERE name = :name', array(':name' => $name))
-        ->fetchField();
-    }
-    // The table might not exist.
-    catch (\Exception $e) {
-      $result = FALSE;
-    }
-    return $result !== FALSE ? unserialize($result) : $default;
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Row.php b/core/modules/migrate/lib/Drupal/migrate/Row.php
deleted file mode 100644
index 53ad14d..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Row.php
+++ /dev/null
@@ -1,264 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Row.
- */
-
-namespace Drupal\migrate;
-
-use Drupal\Component\Utility\NestedArray;
-use Drupal\migrate\Plugin\MigrateIdMapInterface;
-
-/**
- * Stores a row.
- */
-class Row {
-
-  /**
-   * The actual values of the source row.
-   *
-   * @var array
-   */
-  protected $source = array();
-
-  /**
-   * The source identifiers.
-   *
-   * @var array
-   */
-  protected $sourceIds = array();
-
-  /**
-   * The destination values.
-   *
-   * @var array
-   */
-  protected $destination = array();
-
-  /**
-   * The mapping between source and destination identifiers.
-   *
-   * @var array
-   */
-  protected $idMap = array(
-    'original_hash' => '',
-    'hash' => '',
-    'needs_update' => MigrateIdMapInterface::STATUS_NEEDS_UPDATE,
-  );
-
-  /**
-   * Whether the source has been frozen already.
-   *
-   * Once frozen the source can not be changed any more.
-   *
-   * @var bool
-   */
-  protected $frozen = FALSE;
-
-  /**
-   * Constructs a \Drupal\Migrate\Row object.
-   *
-   * @param array $values
-   *   An array of values to add as properties on the object.
-   * @param array $source_ids
-   *   An array containing the IDs of the source using the keys as the field
-   *   names.
-   *
-   * @throws \InvalidArgumentException
-   *   Thrown when a source ID property does not exist.
-   */
-  public function __construct(array $values, array $source_ids) {
-    $this->source = $values;
-    $this->sourceIds = $source_ids;
-    foreach (array_keys($source_ids) as $id) {
-      if (!$this->hasSourceProperty($id)) {
-        throw new \InvalidArgumentException("$id has no value");
-      }
-    }
-  }
-
-  /**
-   * Retrieves the values of the source identifiers.
-   *
-   * @return array
-   *   An array containing the values of the source identifiers.
-   */
-  public function getSourceIdValues() {
-    return array_intersect_key($this->source, $this->sourceIds);
-  }
-
-  /**
-   * Determines whether a source has a property.
-   *
-   * @param string $property
-   *   A property on the source.
-   *
-   * @return bool
-   *   TRUE if the source has property; FALSE otherwise.
-   */
-  public function hasSourceProperty($property) {
-    return isset($this->source[$property]) || array_key_exists($property, $this->source);
-  }
-
-  /**
-   * Retrieves a source property.
-   *
-   * @param string $property
-   *   A property on the source.
-   *
-   * @return mixed|null
-   *   The found returned property or NULL if not found.
-   */
-  public function getSourceProperty($property) {
-    if (isset($this->source[$property])) {
-      return $this->source[$property];
-    }
-  }
-
-  /**
-   * Returns the whole source array.
-   *
-   * @return array
-   *   An array of source plugins.
-   */
-  public function getSource() {
-    return $this->source;
-  }
-
-  /**
-   * Sets a source property.
-   *
-   * This can only be called from the source plugin.
-   *
-   * @param string $property
-   *   A property on the source.
-   * @param mixed $data
-   *   The property value to set on the source.
-   *
-   * @throws \Exception
-   */
-  public function setSourceProperty($property, $data) {
-    if ($this->frozen) {
-      throw new \Exception("The source is frozen and can't be changed any more");
-    }
-    else {
-      $this->source[$property] = $data;
-    }
-  }
-
-  /**
-   * Freezes the source.
-   */
-  public function freezeSource() {
-    $this->frozen = TRUE;
-  }
-
-  /**
-   * Tests if destination property exists.
-   *
-   * @param array|string $property
-   *   An array of properties on the destination.
-   *
-   * @return boolean
-   *   TRUE if the destination property exists.
-   */
-  public function hasDestinationProperty($property) {
-    return NestedArray::keyExists($this->destination, explode(':', $property));
-  }
-
-  /**
-   * Sets destination properties.
-   *
-   * @param string $property
-   *   The name of the destination property.
-   * @param mixed $value
-   *   The property value to set on the destination.
-   */
-  public function setDestinationProperty($property, $value) {
-    NestedArray::setValue($this->destination, explode(':', $property), $value, TRUE);
-  }
-
-  /**
-   * Returns the whole destination array.
-   *
-   * @return array
-   *   An array of destination values.
-   */
-  public function getDestination() {
-    return $this->destination;
-  }
-
-  /**
-   * Returns the value of a destination property.
-   *
-   * @param array|string $property
-   *   An array of properties on the destination.
-   *
-   * @return mixed
-   *  The destination value.
-   */
-  public function getDestinationProperty($property) {
-    return NestedArray::getValue($this->destination, explode(':', $property));
-  }
-
-  /**
-   * Sets the Migrate ID mappings.
-   *
-   * @param array $id_map
-   *   An array of mappings between source ID and destination ID.
-   */
-  public function setIdMap(array $id_map) {
-    $this->idMap = $id_map;
-  }
-
-  /**
-   * Retrieves the Migrate ID mappings.
-   *
-   * @return array
-   *   An array of mapping between source and destination identifiers.
-   */
-  public function getIdMap() {
-    return $this->idMap;
-  }
-
-  /**
-   * Recalculates the hash for the row.
-   */
-  public function rehash() {
-    $this->idMap['original_hash'] = $this->idMap['hash'];
-    $this->idMap['hash'] = hash('sha256', serialize($this->source));
-  }
-
-  /**
-   * Checks whether the row has changed compared to the original ID map.
-   *
-   * @return bool
-   *   TRUE if the row has changed, FALSE otherwise. If setIdMap() was not
-   *   called, this always returns FALSE.
-   */
-  public function changed() {
-    return $this->idMap['original_hash'] != $this->idMap['hash'];
-  }
-
-  /**
-   * Returns if this row needs an update.
-   *
-   * @return bool
-   *   TRUE if the row needs updating, FALSE otherwise.
-   */
-  public function needsUpdate() {
-    return $this->idMap['needs_update'] == MigrateIdMapInterface::STATUS_NEEDS_UPDATE;
-  }
-
-  /**
-   * Returns the hash for the source values..
-   *
-   * @return mixed
-   *   The hash of the source values.
-   */
-  public function getHash() {
-    return $this->idMap['hash'];
-  }
-
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Source.php b/core/modules/migrate/lib/Drupal/migrate/Source.php
deleted file mode 100644
index ebec104..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Source.php
+++ /dev/null
@@ -1,413 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Plugin\migrate\source\SourceBase.
- */
-
-namespace Drupal\migrate;
-
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\Plugin\MigrateIdMapInterface;
-
-/**
- * Source is a caching / decision making wrapper around the source plugin.
- *
- * Derived classes are expected to define __toString(), returning a string
- * describing the source and significant options, i.e. the query.
- *
- * @see \Drupal\migrate\MigrateSourceInterface
- */
-class Source implements \Iterator, \Countable {
-
-  /**
-   * The current row from the quey
-   *
-   * @var \Drupal\Migrate\Row
-   */
-  protected $currentRow;
-
-  /**
-   * The primary key of the current row
-   *
-   * @var array
-   */
-  protected $currentIds;
-
-  /**
-   * Number of rows intentionally ignored (prepareRow() returned FALSE)
-   *
-   * @var int
-   */
-  protected $numIgnored = 0;
-
-  /**
-   * Number of rows we've at least looked at.
-   *
-   * @var int
-   */
-  protected $numProcessed = 0;
-
-  /**
-   * The highwater mark at the beginning of the import operation.
-   *
-   * @var
-   */
-  protected $originalHighwater = '';
-
-  /**
-   * List of source IDs to process.
-   *
-   * @var array
-   */
-  protected $idList = array();
-
-  /**
-   * Whether this instance should cache the source count.
-   *
-   * @var boolean
-   */
-  protected $cacheCounts = FALSE;
-
-  /**
-   * Key to use for caching counts.
-   *
-   * @var string
-   */
-  protected $cacheKey;
-
-  /**
-   * Whether this instance should not attempt to count the source.
-   *
-   * @var boolean
-   */
-  protected $skipCount = FALSE;
-
-  /**
-   * If TRUE, we will maintain hashed source rows to determine whether incoming
-   * data has changed.
-   *
-   * @var bool
-   */
-  protected $trackChanges = FALSE;
-
-  /**
-   * By default, next() will directly read the map row and add it to the data
-   * row. A source plugin implementation may do this itself (in particular, the
-   * SQL source can incorporate the map table into the query) - if so, it should
-   * set this TRUE so we don't duplicate the effort.
-   *
-   * @var bool
-   */
-  protected $mapRowAdded = FALSE;
-
-  /**
-   * @var array
-   */
-  protected $sourceIds;
-
-  /**
-   * @var \Drupal\Core\Cache\CacheBackendInterface
-   */
-  protected $cache;
-
-  /**
-   * @var \Drupal\migrate\Plugin\MigrateIdMapInterface
-   */
-  protected $idMap;
-
-  /**
-   * @var array
-   */
-  protected $highwaterProperty;
-
-  public function getCurrentIds() {
-    return $this->currentIds;
-  }
-
-  public function getIgnored() {
-    return $this->numIgnored;
-  }
-
-  public function getProcessed() {
-    return $this->numProcessed;
-  }
-
-  /**
-   * Reset numIgnored back to 0.
-   */
-  public function resetStats() {
-    $this->numIgnored = 0;
-  }
-
-  /**
-   * Return a count of available source records, from the cache if appropriate.
-   * Returns -1 if the source is not countable.
-   *
-   * @param boolean $refresh
-   * @return int
-   */
-  public function count($refresh = FALSE) {
-    if ($this->skipCount) {
-      return -1;
-    }
-    $source = $this->migration->getSourcePlugin();
-
-    if (!isset($this->cacheKey)) {
-      $this->cacheKey = hash('sha256', (string) $source);
-    }
-
-    // If a refresh is requested, or we're not caching counts, ask the derived
-    // class to get the count from the source.
-    if ($refresh || !$this->cacheCounts) {
-      $count = $source->count();
-      $this->cache->set($this->cacheKey, $count, 'cache');
-    }
-    else {
-      // Caching is in play, first try to retrieve a cached count.
-      $cache_object = $this->cache->get($this->cacheKey, 'cache');
-      if (is_object($cache_object)) {
-        // Success
-        $count = $cache_object->data;
-      }
-      else {
-        // No cached count, ask the derived class to count 'em up, and cache
-        // the result
-        $count = $source->count();
-        $this->cache->set($this->cacheKey, $count, 'cache');
-      }
-    }
-    return $count;
-  }
-
-  /**
-   * Class constructor.
-   *
-   * @param \Drupal\migrate\Entity\MigrationInterface $migration
-   * @param \Drupal\migrate\MigrateExecutable $migrate_executable
-   */
-  function __construct(MigrationInterface $migration, MigrateExecutable $migrate_executable) {
-    $this->migration = $migration;
-    $this->migrateExecutable = $migrate_executable;
-    $configuration = $migration->get('source');
-    if (!empty($configuration['cache_counts'])) {
-      $this->cacheCounts = TRUE;
-    }
-    if (!empty($configuration['skip_count'])) {
-      $this->skipCount = TRUE;
-    }
-    if (!empty($configuration['cache_key'])) {
-      $this->cacheKey = $configuration['cache_key'];
-    }
-    if (!empty($configuration['track_changes'])) {
-      $this->trackChanges = $configuration['track_changes'];
-    }
-  }
-
-  /**
-   * @return \Drupal\Core\Cache\CacheBackendInterface
-   */
-  protected function getCache() {
-    if (!isset($this->cache)) {
-      $this->cache = \Drupal::cache('migrate');
-    }
-    return $this->cache;
-  }
-
-  /**
-   * @return \Iterator
-   */
-  protected function getIterator() {
-    if (!isset($this->iterator)) {
-      $this->iterator = $this->migration->getSourcePlugin()->getIterator();
-    }
-    return $this->iterator;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function current() {
-    return $this->currentRow;
-  }
-
-  /**
-   * Implementation of Iterator::key - called when entering a loop iteration, returning
-   * the key of the current row. It must be a scalar - we will serialize
-   * to fulfill the requirement, but using getCurrentIds() is preferable.
-   */
-  public function key() {
-    return serialize($this->currentIds);
-  }
-
-  /**
-   * Implementation of Iterator::valid() - called at the top of the loop, returning
-   * TRUE to process the loop and FALSE to terminate it
-   */
-  public function valid() {
-    return isset($this->currentRow);
-  }
-
-  /**
-   * Implementation of Iterator::rewind() - subclasses of MigrateSource should
-   * implement performRewind() to do any class-specific setup for iterating
-   * source records.
-   */
-  public function rewind() {
-    $this->idMap = $this->migration->getIdMap();
-    $this->numProcessed = 0;
-    $this->numIgnored = 0;
-    $this->originalHighwater = $this->migration->getHighwater();
-    $this->highwaterProperty = $this->migration->get('highwaterProperty');
-    if ($id_list = $this->migration->get('idlist')) {
-      $this->idList = $id_list;
-    }
-    $this->getIterator()->rewind();
-    $this->next();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function next() {
-    $this->currentIds = NULL;
-    $this->currentRow = NULL;
-
-    while ($this->getIterator()->valid()) {
-      $row_data = $this->getIterator()->current();
-      $this->getIterator()->next();
-      $row = new Row($row_data, $this->migration->get('sourceIds'), $this->migration->get('destinationIds'));
-
-      // Populate the source key for this row
-      $this->currentIds = $row->getSourceIdValues();
-
-      // Pick up the existing map row, if any, unless getNextRow() did it.
-      if (!$this->mapRowAdded && ($id_map = $this->idMap->getRowBySource($this->currentIds))) {
-        $row->setIdMap($id_map);
-      }
-
-      // First, determine if this row should be passed to prepareRow(), or
-      // skipped entirely. The rules are:
-      // 1. If there's an explicit idlist, that's all we care about (ignore
-      //    highwaters and map rows).
-      $prepared = FALSE;
-      if (!empty($this->idList)) {
-        if (in_array(reset($this->currentIds), $this->idList)) {
-          // In the list, fall through.
-        }
-        else {
-          // Not in the list, skip it
-          continue;
-        }
-      }
-      // 2. If the row is not in the map (we have never tried to import it
-      //    before), we always want to try it.
-      elseif (!$row->getIdMap()) {
-        // Fall through
-      }
-      // 3. If the row is marked as needing update, pass it.
-      elseif ($row->needsUpdate()) {
-        // Fall through
-      }
-      // 4. At this point, we have a row which has previously been imported and
-      //    not marked for update. If we're not using highwater marks, then we
-      //    will not take this row. Except, if we're looking for changes in the
-      //    data, we need to go through prepareRow() before we can decide to
-      //    skip it.
-      elseif (!empty($highwater['field'])) {
-        if ($this->trackChanges) {
-          if ($this->prepareRow($row) !== FALSE) {
-            if ($row->changed()) {
-              // This is a keeper
-              $this->currentRow = $row;
-              break;
-            }
-            else {
-              // No change, skip it.
-              continue;
-            }
-          }
-          else {
-            // prepareRow() told us to skip it.
-            continue;
-          }
-        }
-        else {
-          // No highwater and not tracking changes, skip.
-          continue;
-        }
-      }
-      // 5. The initial highwater mark, before anything is migrated, is ''. We
-      //    want to make sure we don't mistakenly skip rows with a highwater
-      //    field value of 0, so explicitly handle '' here.
-      elseif ($this->originalHighwater === '') {
-        // Fall through
-      }
-      // 6. So, we are using highwater marks. Take the row if its highwater
-      //    field value is greater than the saved mark, otherwise skip it.
-      else {
-        // Call prepareRow() here, in case the highwaterField needs preparation
-        if ($this->prepareRow($row) !== FALSE) {
-          if ($row->getSourceProperty($this->highwaterProperty['name']) > $this->originalHighwater) {
-            $this->currentRow = $row;
-            break;
-          }
-          else {
-            // Skip
-            continue;
-          }
-        }
-        $prepared = TRUE;
-      }
-
-      // Allow the Migration to prepare this row. prepareRow() can return boolean
-      // FALSE to ignore this row.
-      if (!$prepared) {
-        if ($this->prepareRow($row) !== FALSE) {
-          // Finally, we've got a keeper.
-          $this->currentRow = $row;
-          break;
-        }
-        else {
-          $this->currentRow = NULL;
-        }
-      }
-    }
-    if ($this->currentRow) {
-      $this->currentRow->freezeSource();
-    }
-    else {
-      $this->currentIds = NULL;
-    }
-  }
-
-  /**
-   * Source classes should override this as necessary and manipulate $keep.
-   *
-   * @param \Drupal\migrate\Row $row
-   */
-  protected function prepareRow(Row $row) {
-    // We're explicitly skipping this row - keep track in the map table
-    if ($this->migration->getSourcePlugin()->prepareRow($row) === FALSE) {
-      // Make sure we replace any previous messages for this item with any
-      // new ones.
-      $id_map = $this->migration->getIdMap();
-      $id_map->delete($this->currentIds, TRUE);
-      $this->migrateExecutable->saveQueuedMessages();
-      $id_map->saveIdMapping($row, array(), MigrateIdMapInterface::STATUS_IGNORED, $this->migrateExecutable->rollbackAction);
-      $this->numIgnored++;
-      $this->currentRow = NULL;
-      $this->currentIds = NULL;
-    }
-    else {
-      // When tracking changed data, We want to quietly skip (rather than
-      // "ignore") rows with changes. The caller needs to make that decision,
-      // so we need to provide them with the necessary information (before and
-      // after hashes).
-      if ($this->trackChanges) {
-        $row->rehash();
-      }
-    }
-    $this->numProcessed++;
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemCron.php b/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemCron.php
deleted file mode 100644
index 9171fff..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemCron.php
+++ /dev/null
@@ -1,59 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\Drupal6SystemCron.
- */
-
-namespace Drupal\migrate\Tests\Dump;
-
-use Drupal\Core\Database\Connection;
-
-/**
- * Database dump for testing system.cron.yml migration.
- */
-class Drupal6SystemCron {
-
-  /**
-   * Sample database schema and values.
-   *
-   * @param \Drupal\Core\Database\Connection $database
-   *   The database connection.
-   */
-  public static function load(Connection $database) {
-    $database->schema()->createTable('variable', array(
-      'fields' => array(
-        'name' => array(
-          'type' => 'varchar',
-          'length' => 128,
-          'not null' => TRUE,
-          'default' => '',
-        ),
-        'value' => array(
-          'type' => 'blob',
-          'not null' => TRUE,
-          'size' => 'big',
-          'translatable' => TRUE,
-        ),
-      ),
-      'primary key' => array(
-        'name',
-      ),
-      'module' => 'system',
-      'name' => 'variable',
-    ));
-    $database->insert('variable')->fields(array(
-      'name',
-      'value',
-    ))
-    ->values(array(
-      'name' => 'cron_threshold_warning',
-      'value' => 'i:172800;',
-    ))
-    ->values(array(
-      'name' => 'cron_threshold_error',
-      'value' => 'i:1209600;',
-    ))
-    ->execute();
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemRss.php b/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemRss.php
deleted file mode 100644
index da4468f..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemRss.php
+++ /dev/null
@@ -1,55 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\Drupal6SystemRss.
- */
-
-namespace Drupal\migrate\Tests\Dump;
-
-use Drupal\Core\Database\Connection;
-
-/**
- * Database dump for testing system.settings.yml migration.
- */
-class Drupal6SystemRss {
-
-  /**
-   * Sample database schema and values.
-   *
-   * @param \Drupal\Core\Database\Connection $database
-   *   The database connection.
-   */
-  public static function load(Connection $database) {
-    $database->schema()->createTable('variable', array(
-      'fields' => array(
-        'name' => array(
-          'type' => 'varchar',
-          'length' => 128,
-          'not null' => TRUE,
-          'default' => '',
-        ),
-        'value' => array(
-          'type' => 'blob',
-          'not null' => TRUE,
-          'size' => 'big',
-          'translatable' => TRUE,
-        ),
-      ),
-      'primary key' => array(
-        'name',
-      ),
-      'module' => 'system',
-      'name' => 'variable',
-    ));
-    $database->insert('variable')->fields(array(
-      'name',
-      'value',
-    ))
-    ->values(array(
-      'name' => 'feed_default_items',
-      'value' => 'i:10;',
-    ))
-    ->execute();
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemSite.php b/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemSite.php
deleted file mode 100644
index 69ef685..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Tests/Dump/Drupal6SystemSite.php
+++ /dev/null
@@ -1,75 +0,0 @@
-<?php
-
-namespace Drupal\migrate\Tests\Dump;
-
-use Drupal\Core\Database\Connection;
-
-/**
- * Database dump for testing system.site.yml migration.
- */
-class Drupal6SystemSite {
-
-  /**
-   * @param \Drupal\Core\Database\Connection $database
-   */
-  public static function load(Connection $database) {
-    $database->schema()->createTable('variable', array(
-      'fields' => array(
-        'name' => array(
-          'type' => 'varchar',
-          'length' => 128,
-          'not null' => TRUE,
-          'default' => '',
-        ),
-        'value' => array(
-          'type' => 'blob',
-          'not null' => TRUE,
-          'size' => 'big',
-          'translatable' => TRUE,
-        ),
-      ),
-      'primary key' => array(
-        'name',
-      ),
-      'module' => 'system',
-      'name' => 'variable',
-    ));
-    $database->insert('variable')->fields(array(
-      'name',
-      'value',
-    ))
-    ->values(array(
-      'name' => 'site_name',
-      'value' => 's:6:"drupal";',
-    ))
-    ->values(array(
-      'name' => 'site_mail',
-      'value' => 's:17:"admin@example.com";',
-    ))
-    ->values(array(
-      'name' => 'site_slogan',
-      'value' => 's:13:"Migrate rocks";',
-    ))
-    ->values(array(
-      'name' => 'site_frontpage',
-      'value' => 's:12:"anonymous-hp";',
-    ))
-    ->values(array(
-      'name' => 'site_403',
-      'value' => 's:4:"user";',
-    ))
-    ->values(array(
-      'name' => 'site_404',
-      'value' => 's:14:"page-not-found";',
-    ))
-    ->values(array(
-      'name' => 'drupal_weight_select_max',
-      'value' => 'i:99;',
-    ))
-    ->values(array(
-      'name' => 'admin_compact_mode',
-      'value' => 'b:0;',
-    ))
-    ->execute();
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Tests/MigrateSystemConfigsTest.php b/core/modules/migrate/lib/Drupal/migrate/Tests/MigrateSystemConfigsTest.php
deleted file mode 100644
index 09529c1..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Tests/MigrateSystemConfigsTest.php
+++ /dev/null
@@ -1,75 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\system\Tests\Upgrade\MigrateSystemSiteTest.
- */
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\migrate\MigrateMessage;
-use Drupal\migrate\MigrateExecutable;
-
-class MigrateSystemConfigsTest extends MigrateTestBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name'  => 'Migrate variables to system.*.yml',
-      'description'  => 'Upgrade variables to system.*.yml',
-      'group' => 'Migrate',
-    );
-  }
-
-  function testSystemSite() {
-    $migration = entity_load('migration', 'd6_system_site');
-    $dumps = array(
-      drupal_get_path('module', 'migrate') . '/lib/Drupal/migrate/Tests/Dump/Drupal6SystemSite.php',
-    );
-    $this->prepare($migration, $dumps);
-    $executable = new MigrateExecutable($migration, new MigrateMessage);
-    $executable->import();
-    $config = \Drupal::config('system.site');
-    $this->assertIdentical($config->get('name'), 'drupal');
-    $this->assertIdentical($config->get('mail'), 'admin@example.com');
-    $this->assertIdentical($config->get('slogan'), 'Migrate rocks');
-    $this->assertIdentical($config->get('page.front'), 'anonymous-hp');
-    $this->assertIdentical($config->get('page.403'), 'user');
-    $this->assertIdentical($config->get('page.404'), 'page-not-found');
-    $this->assertIdentical($config->get('weight_select_max'), 99);
-    $this->assertIdentical($config->get('admin_compact_mode'), FALSE);
-  }
-
-  /**
-   * Tests migration of system (cron) variables to system.cron.yml.
-   */
-  public function testSystemCron() {
-    $migration = entity_load('migration', 'd6_system_cron');
-    $dumps = array(
-      drupal_get_path('module', 'migrate') . '/lib/Drupal/migrate/Tests/Dump/Drupal6SystemCron.php',
-    );
-    $this->prepare($migration, $dumps);
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
-    $executable->import();
-    $config = \Drupal::config('system.cron');
-    $this->assertIdentical($config->get('threshold.warning'), 172800);
-    $this->assertIdentical($config->get('threshold.error'), 1209600);
-  }
-
-  /**
-   * Tests migration of system (rss) variables to system.rss.yml.
-   */
-  public function testSystemRss() {
-    $migration = entity_load('migration', 'd6_system_rss');
-    $dumps = array(
-      drupal_get_path('module', 'migrate') . '/lib/Drupal/migrate/Tests/Dump/Drupal6SystemRss.php',
-    );
-    $this->prepare($migration, $dumps);
-    $executable = new MigrateExecutable($migration, new MigrateMessage());
-    $executable->import();
-    $config = \Drupal::config('system.rss');
-    $this->assertIdentical($config->get('items.limit'), 10);
-  }
-}
diff --git a/core/modules/migrate/lib/Drupal/migrate/Tests/MigrateTestBase.php b/core/modules/migrate/lib/Drupal/migrate/Tests/MigrateTestBase.php
deleted file mode 100644
index 5b67e5a..0000000
--- a/core/modules/migrate/lib/Drupal/migrate/Tests/MigrateTestBase.php
+++ /dev/null
@@ -1,60 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\system\Tests\Upgrade\MigrateTestBase.
- */
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\Core\Database\Database;
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\Plugin\migrate\source\SqlBase;
-use Drupal\simpletest\WebTestBase;
-
-class MigrateTestBase extends WebTestBase {
-
-  /**
-   * The file path(s) to the dumped database(s) to load into the child site.
-   *
-   * @var array
-   */
-  var $databaseDumpFiles = array();
-
-  public static $modules = array('migrate');
-
-  /**
-   * @param MigrationInterface $migration
-   * @param array $files
-   *
-   * @return \Drupal\Core\Database\Connection
-   */
-  protected function prepare(MigrationInterface $migration, array $files = array()) {
-    $databasePrefix = 'm_';
-    $connection_info = Database::getConnectionInfo('default');
-    foreach ($connection_info as $target => $value) {
-      $connection_info[$target]['prefix'] = array(
-        'default' => $value['prefix']['default'] . $databasePrefix,
-      );
-    }
-    $database = SqlBase::getDatabaseConnection($migration->id(), array('database' => $connection_info['default']));
-    foreach (array('source', 'destination', 'idMap') as $key) {
-      $configuration = $migration->get($key);
-      $configuration['database'] = $database;
-      $migration->set($key, $configuration);
-    }
-
-    // Load the database from the portable PHP dump.
-    // The files may be gzipped.
-    foreach ($files as $file) {
-      if (substr($file, -3) == '.gz') {
-        $file = "compress.zlib://$file";
-        require $file;
-      }
-      preg_match('/^namespace (.*);$/m', file_get_contents($file), $matches);
-      $class = $matches[1] . '\\' . basename($file, '.php');
-      $class::load($database);
-    }
-    return $database;
-  }
-}
diff --git a/core/modules/migrate/migrate.api.php b/core/modules/migrate/migrate.api.php
deleted file mode 100644
index a2d2cb5..0000000
--- a/core/modules/migrate/migrate.api.php
+++ /dev/null
@@ -1,37 +0,0 @@
-<?php
-
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\Plugin\MigrateSourceInterface;
-use Drupal\migrate\Row;
-
-/**
- * @file
- * Hooks provided by the Migrate module.
- */
-
-/**
- * @addtogroup hooks
- * @{
- */
-
-/**
- * Allows adding data to a row before processing it.
- *
- * For example, filter module used to store filter format settings in the
- * variables table which now needs to be inside the filter format config
- * file. So, it needs to be added here.
- *
- * hook_migrate_MIGRATION_ID_prepare_row is also available.
- */
-function hook_migrate_prepare_row(Row $row, MigrateSourceInterface $source, MigrationInterface $migration) {
-  if ($migration->id() == 'drupal6_filter_formats') {
-    $value = $source->getDatabase()->query('SELECT value FROM {variable} WHERE name = :name', array(':name' => 'mymodule_filter_foo_' . $row->getSourceProperty('format')))->fetchField();
-    if ($value) {
-      $row->setSourceProperty('settings:mymodule:foo', unserialize($value));
-    }
-  }
-}
-
-/**
- * @} End of "addtogroup hooks".
- */
diff --git a/core/modules/migrate/migrate.info.yml b/core/modules/migrate/migrate.info.yml
deleted file mode 100644
index 460f66b..0000000
--- a/core/modules/migrate/migrate.info.yml
+++ /dev/null
@@ -1,7 +0,0 @@
-name: Migrate
-type: module
-description: 'Handles migrations'
-package: Core
-version: VERSION
-core: 8.x
-;configure: admin/structure/migrate
diff --git a/core/modules/migrate/migrate.module b/core/modules/migrate/migrate.module
deleted file mode 100644
index e69de29..0000000
diff --git a/core/modules/migrate/migrate.services.yml b/core/modules/migrate/migrate.services.yml
deleted file mode 100644
index 28848df..0000000
--- a/core/modules/migrate/migrate.services.yml
+++ /dev/null
@@ -1,23 +0,0 @@
-services:
-  cache.migrate:
-    class: Drupal\Core\Cache\CacheBackendInterface
-    tags:
-      - { name: cache.bin }
-    factory_method: get
-    factory_service: cache_factory
-    arguments: [migrate]
-  plugin.manager.migrate.source:
-    class: Drupal\migrate\Plugin\MigratePluginManager
-    arguments: [source, '@container.namespaces', '@cache.cache', '@language_manager', '@module_handler']
-  plugin.manager.migrate.process:
-    class: Drupal\migrate\Plugin\MigratePluginManager
-    arguments: [process, '@container.namespaces', '@cache.cache', '@language_manager', '@module_handler']
-  plugin.manager.migrate.destination:
-    class: Drupal\migrate\Plugin\MigratePluginManager
-    arguments: [destination, '@container.namespaces', '@cache.cache', '@language_manager', '@module_handler']
-  plugin.manager.migrate.id_map:
-    class: Drupal\migrate\Plugin\MigratePluginManager
-    arguments: [id_map, '@container.namespaces', '@cache.cache', '@language_manager', '@module_handler']
-  plugin.manager.migrate.entity_field:
-    class: Drupal\migrate\Plugin\MigratePluginManager
-    arguments: [entity_field, '@container.namespaces', '@cache.cache', '@language_manager', '@module_handler']
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/ConditionResolver.php b/core/modules/migrate/tests/Drupal/migrate/Tests/ConditionResolver.php
deleted file mode 100644
index 875f13e..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/ConditionResolver.php
+++ /dev/null
@@ -1,93 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\ConditionResolver.
- */
-
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\Core\Database\Query\Condition;
-
-class ConditionResolver {
-
-  /**
-   * Match a row against a group of conditions.
-   *
-   * @param \Drupal\migrate\tests\DatabaseRowInterface $row
-   *
-   * @param \Drupal\Core\Database\Query\Condition $condition_group
-   *
-   * @return bool
-   */
-  public static function matchGroup(DatabaseRowInterface $row, Condition $condition_group) {
-    $conditions = $condition_group->conditions();
-    $and = $conditions['#conjunction'] == 'AND';
-    unset($conditions['#conjunction']);
-    $match = TRUE;
-    foreach ($conditions as $condition) {
-      $match = $condition['field'] instanceof Condition ? static::matchGroup($row, $condition['field']) : static::matchSingle($row, $condition);
-      // For AND, finish matching on the first fail. For OR, finish on first
-      // success.
-      if ($and != $match) {
-        break;
-      }
-    }
-    return $match;
-  }
-
-  /**
-   * Match a single row and its condition.
-   *
-   * @param \Drupal\migrate\tests\DatabaseRowInterface $row
-   *   The row to match.
-   *
-   * @param array $condition
-   *   An array representing a single condition.
-   *
-   * @return bool
-   *   TRUE if the condition matches.
-   *
-   * @throws \Exception
-   *
-   */
-  protected static function matchSingle(DatabaseRowInterface $row, array $condition) {
-    $row_value = $row->getValue($condition['field']);
-    switch ($condition['operator']) {
-      case '=':
-        return $row_value == $condition['value'];
-
-      case '<=':
-        return $row_value <= $condition['value'];
-
-      case '>=':
-        return $row_value >= $condition['value'];
-
-      case '!=':
-        return $row_value != $condition['value'];
-
-      case '<>':
-        return $row_value != $condition['value'];
-
-      case '<':
-        return $row_value < $condition['value'];
-
-      case '>':
-        return $row_value > $condition['value'];
-
-      case 'IN':
-        return in_array($row_value, $condition['value']);
-
-      case 'IS NULL':
-        return !isset($row_value);
-
-      case 'IS NOT NULL':
-        return isset($row_value);
-
-      default:
-        throw new \Exception(sprintf('operator %s is not supported', $condition['operator']));
-    }
-  }
-
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/D6VariableTest.php b/core/modules/migrate/tests/Drupal/migrate/Tests/D6VariableTest.php
deleted file mode 100644
index cc903bf..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/D6VariableTest.php
+++ /dev/null
@@ -1,75 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\D6VariableSourceTest.
- */
-
-namespace Drupal\migrate\Tests;
-
-/**
- * @group migrate
- * @group Drupal
- */
-class D6VariableTest extends MigrateSqlSourceTestCase {
-
-  const PLUGIN_CLASS = 'Drupal\migrate\Plugin\migrate\source\D6Variable';
-
-  protected $migrationConfiguration = array(
-    'id' => 'test',
-    'highwaterProperty' => array('field' => 'test'),
-    'idlist' => array(),
-    'source' => array(
-      'plugin' => 'drupal6_variable',
-      'variables' => array(
-        'foo',
-        'bar',
-      ),
-    ),
-    'sourceIds' => array(),
-    'destinationIds' => array(),
-  );
-
-  protected $mapJoinable = FALSE;
-
-  protected $expectedResults = array(
-    array(
-      'foo' => 1,
-      'bar' => FALSE,
-    ),
-  );
-
-  protected $databaseContents = array(
-    'variable' => array(
-      array('name' => 'foo', 'value' => 'i:1;'),
-      array('name' => 'bar', 'value' => 'b:0;'),
-    ),
-  );
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'D6 variable source functionality',
-      'description' => 'Tests D6 variable source plugin.',
-      'group' => 'Migrate',
-    );
-  }
-
-}
-
-namespace Drupal\migrate\Tests\source;
-
-use Drupal\Core\Database\Connection;
-use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\migrate\Plugin\migrate\source\D6Variable;
-
-class TestD6Variable extends D6Variable {
-  function setDatabase(Connection $database) {
-    $this->database = $database;
-  }
-  function setModuleHandler(ModuleHandlerInterface $module_handler) {
-    $this->moduleHandler = $module_handler;
-  }
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRow.php b/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRow.php
deleted file mode 100644
index 1c8cf76..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRow.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\DatabaseRow.
- */
-
-namespace Drupal\migrate\Tests;
-
-class DatabaseRow implements DatabaseRowInterface {
-
-  public function __construct(array $row) {
-    $this->row = $row;
-  }
-
-  public function getValue($field) {
-    return $this->row[$field];
-  }
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRowInterface.php b/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRowInterface.php
deleted file mode 100644
index cddfa8b..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRowInterface.php
+++ /dev/null
@@ -1,13 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\DatabaseRowInterface.
- */
-
-namespace Drupal\migrate\Tests;
-
-interface DatabaseRowInterface {
-
-  function getValue($field);
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRowSelect.php b/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRowSelect.php
deleted file mode 100644
index d4772ab..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/DatabaseRowSelect.php
+++ /dev/null
@@ -1,28 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\DatabaseRowSelect.
- */
-
-namespace Drupal\migrate\Tests;
-
-class DatabaseRowSelect extends DatabaseRow {
-
-  public function __construct(array $row, array $fieldsWithTable, array $fields) {
-    $this->fieldsWithTable = $fieldsWithTable;
-    $this->fields = $fields;
-    parent::__construct($row);
-  }
-
-  public function getValue($field) {
-    $field_info = isset($this->fieldsWithTable[$field]) ? $this->fieldsWithTable[$field] : $this->fields[$field];
-    if (array_key_exists($field_info['field'], $this->row[$field_info['table']]['result'])) {
-      $index = 'result';
-    }
-    else {
-      $index = 'all';
-    }
-    return $this->row[$field_info['table']][$index][$field_info['field']];
-  }
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/FakeDatabaseSchema.php b/core/modules/migrate/tests/Drupal/migrate/Tests/FakeDatabaseSchema.php
deleted file mode 100644
index 1433f18..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/FakeDatabaseSchema.php
+++ /dev/null
@@ -1,149 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\FakeSelect.
- */
-
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\Core\Database\Schema;
-
-class FakeDatabaseSchema extends Schema {
-
-  /**
-   * As set on MigrateSqlSourceTestCase::databaseContents.
-   */
-  protected $databaseContents;
-
-  public function __construct($database_contents) {
-    $this->uniqueIdentifier = uniqid('', TRUE);
-    // @todo Maybe we can generate an internal representation.
-    $this->databaseContents = $database_contents;
-  }
-
-  public function tableExists($table) {
-    return in_array($table, array_keys($this->databaseContents));
-  }
-
-  public function prefixNonTable($table) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  protected function buildTableNameCondition($table_name, $operator = '=', $add_prefix = TRUE) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  protected function getPrefixInfo($table = 'default', $add_prefix = TRUE) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function addField($table, $field, $spec, $keys_new = array()) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function addIndex($table, $name, $fields) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function addPrimaryKey($table, $fields) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function addUniqueKey($table, $name, $fields) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function changeField($table, $field, $field_new, $spec, $keys_new = array()) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function __clone() {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function copyTable($source, $destination) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function createTable($name, $table) {
-    #throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function dropField($table, $field) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function dropIndex($table, $name) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function dropPrimaryKey($table) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function dropTable($table) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function dropUniqueKey($table, $name) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function fieldExists($table, $column) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function fieldNames($fields) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function fieldSetDefault($table, $field, $default) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function fieldSetNoDefault($table, $field) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function findTables($table_expression) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function getFieldTypeMap() {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function indexExists($table, $name) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function nextPlaceholder() {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function prepareComment($comment, $length = NULL) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function renameTable($table, $new_name) {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  public function uniqueIdentifier() {
-    throw new \Exception(sprintf('Unsupported method "%s"', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'Fake database schema',
-      'description' => 'Tests for fake database schema plugin.',
-      'group' => 'Migrate',
-    );
-  }
-
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/FakeSelect.php b/core/modules/migrate/tests/Drupal/migrate/Tests/FakeSelect.php
deleted file mode 100644
index 9b79234..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/FakeSelect.php
+++ /dev/null
@@ -1,511 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\FakeSelect.
- */
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\Core\Database\Connection;
-use Drupal\Core\Database\Query\Condition;
-use Drupal\Core\Database\Query\PlaceholderInterface;
-use Drupal\Core\Database\Query\Select;
-use Drupal\Core\Database\Query\SelectInterface;
-
-class FakeSelect extends Select {
-
-  /**
-   * Contents of the pseudo-database.
-   *
-   * Keys are table names and values are arrays of rows in the table.
-   * Every row there contains all table fields keyed by field name.
-   *
-   * @code
-   * array(
-   *   'user' => array(
-   *     array(
-   *       'uid' => 1,
-   *       'name' => 'admin',
-   *     ),
-   *     array(
-   *       'uid' => 2,
-   *       'name' => 'alice',
-   *     ),
-   *   ),
-   *   'node' => array(
-   *     array(
-   *       'nid' => 1,
-   *     )
-   *   )
-   * )
-   * @endcode
-   *
-   * @var array
-   */
-  protected $databaseContents;
-
-  protected $countQuery = FALSE;
-  protected $fieldsWithTable = array();
-
-  /**
-   * Constructs a new FakeSelect.
-   *
-   * @param string $table
-   *   The base table name used within fake select.
-   *
-   * @param string $alias
-   *   The base table alias used within fake select.
-   *
-   * @param array $database_contents
-   *   An array of mocked database content.
-   *
-   * @param string $conjunction
-   *   The operator to use to combine conditions: 'AND' or 'OR'.
-   */
-  public function __construct($table, $alias, array $database_contents, $conjunction = 'AND') {
-    $this->addJoin(NULL, $table, $alias);
-    $this->where = new Condition($conjunction);
-    $this->having = new Condition($conjunction);
-    $this->databaseContents = $database_contents;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function leftJoin($table, $alias = NULL, $condition = NULL, $arguments = array()) {
-    return $this->addJoin('LEFT', $table, $alias, $condition, $arguments);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function addJoin($type, $table, $alias = NULL, $condition = NULL, $arguments = array()) {
-    if ($table instanceof SelectInterface) {
-      // @todo implement this.
-      throw new \Exception('Subqueries are not supported at this moment.');
-    }
-    $alias = parent::addJoin($type, $table, $alias, $condition, $arguments);
-    if (isset($type)) {
-      if ($type != 'INNER' && $type != 'LEFT') {
-        throw new \Exception(sprintf('%s type not supported, only INNER and LEFT.', $type));
-      }
-      if (!preg_match('/(\w+)\.(\w+)\s*=\s*(\w+)\.(\w+)/', $condition, $matches)) {
-        throw new \Exception('Only x.field1 = y.field2 conditions are supported.' . $condition);
-      }
-      if ($matches[1] == $alias) {
-        $this->tables[$alias] += array(
-          'added_field' => $matches[2],
-          'original_table_alias' => $matches[3],
-          'original_field' => $matches[4],
-        );
-      }
-      elseif ($matches[3] == $alias) {
-        $this->tables[$alias] += array(
-          'added_field' => $matches[4],
-          'original_table_alias' => $matches[1],
-          'original_field' => $matches[2],
-        );
-      }
-      else {
-        throw new \Exception('The JOIN condition does not contain the alias of the joined table.');
-      }
-    }
-    return $alias;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function execute() {
-    // @todo: Implement distinct() handling.
-
-    // Single table count queries often do not contain fields which this class
-    // does not support otherwise, so add a shortcut.
-    if (count($this->tables) == 1 && $this->countQuery) {
-      $table_info = reset($this->tables);
-      $where = $this->where;
-      if (!empty($this->databaseContents[$table_info['table']])) {
-        $results = array_filter($this->databaseContents[$table_info['table']], function ($row_array) use ($where) {
-          return ConditionResolver::matchGroup(new DatabaseRow($row_array), $where);
-        });
-      }
-      else {
-        $results = array();
-      }
-    }
-    else {
-      $all_rows = $this->executeJoins();
-      $all_rows = $this->resolveConditions($this->where, $all_rows);
-      if (!empty($this->order)) {
-        usort($all_rows, array($this, 'sortCallback'));
-      }
-      // Now flatten the rows so that each row becomes a field alias => value
-      // array.
-      $results = array();
-      foreach ($all_rows as $table_rows) {
-        $result_row = array();
-        foreach ($table_rows as $row) {
-          $result_row += $row['result'];
-        }
-        $results[] = $result_row;
-      }
-    }
-    if (!empty($this->range)) {
-      $results = array_slice($results, $this->range['start'], $this->range['length']);
-    }
-    if ($this->countQuery) {
-      $results = array(array(count($results)));
-    }
-    return new FakeStatement($results);
-  }
-
-  /**
-   * Create an initial result set by executing the joins and picking fields.
-   *
-   * @return array
-   *   A multidimensional array, the first key are table aliases, the second
-   *   are field aliases, the values are the database contents or NULL in case
-   *   of JOINs.
-   */
-  protected function executeJoins() {
-    // @TODO add support for all_fields.
-    $fields = array();
-    foreach ($this->fields as $field_info) {
-      $this->fieldsWithTable[$field_info['table'] . '.' . $field_info['field']] = $field_info;
-      $fields[$field_info['table']][$field_info['field']] = NULL;
-    }
-    foreach ($this->tables as $alias => $table_info) {
-      if ($table = reset($this->databaseContents[$table_info['table']])) {
-        foreach (array_keys($table) as $field) {
-          if (!isset($this->fields[$field])) {
-            $this->fieldsWithTable[$field] = array(
-              'table' => $alias,
-              'field' => $field,
-            );
-          }
-        }
-      }
-    }
-    // This will contain a multiple dimensional array. The first key will be a
-    // table alias, the second either result or all, the third will be a field
-    // alias. all contains every field in the table with the original field
-    // names while result contains only the fields requested. This allows for
-    // filtering on fields that were not added via addField().
-    $results = array();
-    foreach ($this->tables as $table_alias => $table_info) {
-      // The base table for this query.
-      if (empty($table_info['join type'])) {
-        foreach ($this->databaseContents[$table_info['table']] as $candidate_row) {
-          $results[] = $this->getNewRow($table_alias, $fields, $candidate_row);
-        }
-      }
-      else {
-        $new_rows = array();
-
-        // Dynamically build a set of joined rows. Check existing rows and see
-        // if they can be joined with incoming rows.
-        foreach ($results as $row) {
-          $joined = FALSE;
-          foreach ($this->databaseContents[$table_info['table']] as $candidate_row) {
-            if ($row[$table_info['original_table_alias']]['result'][$table_info['original_field']] == $candidate_row[$table_info['added_field']]) {
-              $joined = TRUE;
-              $new_rows[] = $this->getNewRow($table_alias, $fields, $candidate_row, $row);
-            }
-          }
-          if (!$joined && $table_info['join type'] == 'LEFT') {
-            // Because PHP doesn't scope their foreach statements,
-            // $candidate_row may contain the last value assigned to it from the
-            // previous statement.
-            // @TODO: empty tables? Those are a problem.
-            $keys = array_keys($candidate_row);
-            $values = array_fill(0, count($keys), NULL);
-            $new_row = array(
-              'result' => $fields[$table_alias],
-              'all' => array_combine($keys, $values),
-            );
-            $new_rows[] = array($table_alias => $new_row) + $row;
-          }
-        }
-        $results = $new_rows;
-      }
-    }
-    return $results;
-  }
-
-  /**
-   * Retrieves a new row.
-   *
-   * @param string $table_alias
-   * @param array $fields
-   * @param array $candidate_row
-   * @param array $row
-   *
-   * @return array
-   */
-  protected function getNewRow($table_alias, $fields, $candidate_row, $row = array()) {
-    $new_row[$table_alias]['all'] = $candidate_row;
-    foreach ($fields[$table_alias] as $field => $v) {
-      $new_row[$table_alias]['result'][$field] = $candidate_row[$field];
-    }
-    return $new_row + $row;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function countQuery() {
-    $query = clone $this;
-    return $query->setCountQuery();
-  }
-
-  /**
-   * Set this query to be a count query.
-   */
-  protected function setCountQuery() {
-    $this->countQuery = TRUE;
-    return $this;
-  }
-
-  /**
-   * usort callback to order the results.
-   */
-  protected function sortCallback($a, $b) {
-    $a_row = new DatabaseRowSelect($a, $this->fieldsWithTable, $this->fields);
-    $b_row = new DatabaseRowSelect($b, $this->fieldsWithTable, $this->fields);
-    foreach ($this->order as $field => $direction) {
-      $a_value = $a_row->getValue($field);
-      $b_value = $b_row->getValue($field);
-      if ($a_value != $b_value) {
-        return (($a_value < $b_value) == ($direction == 'ASC')) ? -1 : 1;
-      }
-    }
-    return 0;
-  }
-
-  /**
-   * Resolves conditions by removing non-matching rows.
-   *
-   * @param \Drupal\Core\Database\Query\Condition $condition_group
-   *   The condition group to check.
-   * @param array $rows
-   *   An array of rows excluding non-matching rows.
-   */
-  protected function resolveConditions(Condition $condition_group, array &$rows) {
-    $fields_with_table = $this->fieldsWithTable;
-    $fields = $this->fields;
-    return array_filter($rows, function ($row_array) use ($condition_group, $fields_with_table, $fields) {
-      $row = new DatabaseRowSelect($row_array, $fields_with_table, $fields);
-      return ConditionResolver::matchGroup($row, $condition_group);
-    });
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function orderBy($field, $direction = 'ASC') {
-    $this->order[$field] = strtoupper($direction);
-    return $this;
-  }
-
-  // ================== we could support these.
-  /**
-   * {@inheritdoc}
-   */
-  public function groupBy($field) {
-    // @todo: Implement groupBy() method.
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function havingCondition($field, $value = NULL, $operator = NULL) {
-    // @todo: Implement havingCondition() method.
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function uniqueIdentifier() {
-    // TODO: Implement uniqueIdentifier() method.
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  // ================== the rest won't be supported, ever.
-  /**
-   * {@inheritdoc}
-   */
-  public function nextPlaceholder() {
-    // TODO: Implement nextPlaceholder() method.
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function isPrepared() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function preExecute(SelectInterface $query = NULL) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function where($snippet, $args = array()) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function extend($extender_name) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function &getExpressions() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function &getGroupBy() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function &getUnion() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function forUpdate($set = TRUE) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function rightJoin($table, $alias = NULL, $condition = NULL, $arguments = array()) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function &conditions() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function orderRandom() {
-    // We could implement this but why bother.
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function union(SelectInterface $query, $type = '') {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function addExpression($expression, $alias = NULL, $arguments = array()) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function &getTables() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getArguments(PlaceholderInterface $query_place_holder = NULL) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function &getOrderBy() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function &getFields() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function exists(SelectInterface $select) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function notExists(SelectInterface $select) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function arguments() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function compile(Connection $connection, PlaceholderInterface $query_place_holder) {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function compiled() {
-    throw new \Exception(sprintf('Method "%s" is not supported', __METHOD__));
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'Fake select test',
-      'description' => 'Tests for fake select plugin.',
-      'group' => 'Migrate',
-    );
-  }
-
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/FakeStatement.php b/core/modules/migrate/tests/Drupal/migrate/Tests/FakeStatement.php
deleted file mode 100644
index 9088c50..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/FakeStatement.php
+++ /dev/null
@@ -1,103 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\FakeStatement.
- */
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\Core\Database\StatementInterface;
-
-/**
- * Represents a fake prepared statement.
- */
-class FakeStatement extends \ArrayIterator implements StatementInterface {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function execute($args = array(), $options = array()) {
-    throw new \Exception('This method is not supported');
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getQueryString() {
-    throw new \Exception('This method is not supported');
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function rowCount() {
-    return $this->count();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function fetchField($index = 0) {
-    $row = array_values($this->current());
-    $return = $row[$index];
-    $this->next();
-    return $return;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function fetchAssoc() {
-    $return = $this->current();
-    $this->next();
-    return $return;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function fetchCol($index = 0) {
-    $return = array();
-    foreach ($this as $row) {
-      $row = array_values($row);
-      $return[] = $row[$index];
-    }
-    return $return;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function fetchAllKeyed($key_index = 0, $value_index = 1) {
-    $return = array();
-    foreach ($this as $row) {
-      $row = array_values($row);
-      $return[$row[$key_index]] = $row[$value_index];
-    }
-    return $return;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function fetchAllAssoc($key, $fetch = NULL) {
-    $return = array();
-    foreach ($this as $row) {
-      $return[$row[$key]] = $row;
-    }
-    return $return;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'Fake statement test',
-      'description' => 'Tests for fake statement plugin.',
-      'group' => 'Migrate',
-    );
-  }
-
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateExecutableTest.php b/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateExecutableTest.php
deleted file mode 100644
index 295ed6d..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateExecutableTest.php
+++ /dev/null
@@ -1,104 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\MigrateExecutableTest.
- */
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\Core\StringTranslation\TranslationInterface;
-use Drupal\migrate\Entity\MigrationInterface;
-use Drupal\migrate\MigrateExecutable;
-
-/**
- * Tests the migrate executable.
- *
- * @group Drupal
- * @group migrate
- *
- * @covers \Drupal\migrate\Tests\MigrateExecutableTest
- */
-class MigrateExecutableTest extends MigrateTestCase {
-
-  /**
-   * The mocked migration entity.
-   *
-   * @var \Drupal\migrate\Entity\MigrationInterface|\PHPUnit_Framework_MockObject_MockObject
-   */
-  protected $migration;
-
-  /**
-   * The mocked migrate message.
-   *
-   * @var \Drupal\migrate\MigrateMessageInterface|\PHPUnit_Framework_MockObject_MockObject
-   */
-  protected $message;
-
-  /**
-   * The tested migrate executable.
-   *
-   * @var \Drupal\migrate\MigrateExecutable
-   */
-  protected $executable;
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'Migrate executable',
-      'description' => 'Tests the migrate executable.',
-      'group' => 'Migrate',
-    );
-  }
-
-  protected function setUp() {
-    $this->migration = $this->getMock('Drupal\migrate\Entity\MigrationInterface');
-    $this->message = $this->getMock('Drupal\migrate\MigrateMessageInterface');
-    $id_map = $this->getMock('Drupal\migrate\Plugin\MigrateIdMapInterface');
-
-    $this->migration->expects($this->any())
-      ->method('getIdMap')
-      ->will($this->returnValue($id_map));
-
-    $this->executable = new TestMigrateExecutable($this->migration, $this->message);
-    $this->executable->setTranslationManager($this->getStringTranslationStub());
-  }
-
-  /**
-   * Tests an import with an incomplete rewinding.
-   */
-  public function testImportWithFailingRewind() {
-    $iterator = $this->getMock('\Iterator');
-    $iterator->expects($this->once())
-      ->method('valid')
-      ->will($this->returnCallback(function() {
-        throw new \Exception('invalid source iteration');
-      }));
-    $source = $this->getMock('Drupal\migrate\Plugin\MigrateSourceInterface');
-    $source->expects($this->any())
-      ->method('getIterator')
-      ->will($this->returnValue($iterator));
-
-    $this->migration->expects($this->any())
-      ->method('getSourcePlugin')
-      ->will($this->returnValue($source));
-
-    // Ensure that a message with the proper message was added.
-    $this->message->expects($this->once())
-      ->method('display')
-      ->with('Migration failed with source plugin exception: invalid source iteration');
-
-    $result = $this->executable->import();
-    $this->assertEquals(MigrationInterface::RESULT_FAILED, $result);
-  }
-
-}
-
-class TestMigrateExecutable extends MigrateExecutable {
-
-  public function setTranslationManager(TranslationInterface $translation_manager) {
-    $this->translationManager = $translation_manager;
-  }
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateSqlSourceTestCase.php b/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateSqlSourceTestCase.php
deleted file mode 100644
index 1456977..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateSqlSourceTestCase.php
+++ /dev/null
@@ -1,88 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\MigrateSqlSourceTestCase.
- */
-
-namespace Drupal\migrate\Tests;
-
-/**
- * Provides setup and helper methods for Migrate module source tests.
- */
-abstract class MigrateSqlSourceTestCase extends MigrateTestCase {
-
-  /**
-   * The tested source plugin.
-   *
-   * @var \Drupal\migrate\Plugin\migrate\source\d6\Comment.
-   */
-  protected $source;
-
-  protected $databaseContents = array();
-
-  const PLUGIN_CLASS = '';
-
-  const ORIGINAL_HIGHWATER = '';
-
-  protected $expectedResults = array();
-
-  /**
-   * @var \Drupal\migrate\Plugin\MigrateSourceInterface
-   */
-  protected $plugin;
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    $module_handler = $this->getMockBuilder('Drupal\Core\Extension\ModuleHandlerInterface')
-      ->disableOriginalConstructor()
-      ->getMock();
-
-    $migration = $this->getMigration();
-    $migration->expects($this->any())
-      ->method('getHighwater')
-      ->will($this->returnValue(static::ORIGINAL_HIGHWATER));
-    // Need the test class, not the original because we need a setDatabase method. This is not pretty :/
-    $plugin_class  = preg_replace('/^(Drupal\\\\\w+\\\\)Plugin\\\\migrate(\\\\source(\\\\.+)?\\\\)([^\\\\]+)$/', '\1Tests\2Test\4', static::PLUGIN_CLASS);
-    $plugin = new $plugin_class($this->migrationConfiguration['source'], $this->migrationConfiguration['source']['plugin'], array(), $migration);
-    $plugin->setDatabase($this->getDatabase($this->databaseContents + array('test_map' => array())));
-    $plugin->setModuleHandler($module_handler);
-    $migration->expects($this->any())
-      ->method('getSourcePlugin')
-      ->will($this->returnValue($plugin));
-    $migrateExecutable = $this->getMockBuilder('Drupal\migrate\MigrateExecutable')
-      ->disableOriginalConstructor()
-      ->getMock();
-    $this->source = new TestSource($migration, $migrateExecutable);
-
-    $cache = $this->getMock('Drupal\Core\Cache\CacheBackendInterface');
-    $this->source->setCache($cache);
-  }
-
-  public function testRetrieval() {
-    $this->queryResultTest($this->source, $this->expectedResults);
-  }
-
-  /**
-   * @param \Drupal\migrate\Row $row
-   * @param string $key
-   * @return mixed
-   */
-  protected function getValue($row, $key) {
-    return $row->getSourceProperty($key);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'SQL source test',
-      'description' => 'Tests for SQL source plugin.',
-      'group' => 'Migrate',
-    );
-  }
-
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateTestCase.php b/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateTestCase.php
deleted file mode 100644
index 7ca0ae6..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/MigrateTestCase.php
+++ /dev/null
@@ -1,141 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\MigrateTestCase.
- */
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\Tests\UnitTestCase;
-
-/**
- * Provides setup and helper methods for Migrate module tests.
- */
-abstract class MigrateTestCase extends UnitTestCase {
-
-  /**
-   * @TODO: does this need to be derived from the source/destination plugin?
-   *
-   * @var bool
-   */
-  protected $mapJoinable = TRUE;
-
-  protected $migrationConfiguration = array();
-
-  /**
-   * Retrieve a mocked migration.
-   *
-   * @return \Drupal\migrate\Entity\MigrationInterface
-   *   The mocked migration.
-   */
-  protected function getMigration() {
-    $idmap = $this->getMock('Drupal\migrate\Plugin\MigrateIdMapInterface');
-    if ($this->mapJoinable) {
-      $idmap->expects($this->once())
-        ->method('getQualifiedMapTable')
-        ->will($this->returnValue('test_map'));
-    }
-
-    $migration = $this->getMock('Drupal\migrate\Entity\MigrationInterface');
-    $migration->expects($this->any())
-      ->method('getIdMap')
-      ->will($this->returnValue($idmap));
-    $configuration = $this->migrationConfiguration;
-    $migration->expects($this->any())->method('get')->will($this->returnCallback(function ($argument) use ($configuration) {
-      return isset($configuration[$argument]) ? $configuration[$argument] : '';
-    }));
-    $migration->expects($this->any())
-      ->method('id')
-      ->will($this->returnValue($configuration['id']));
-    return $migration;
-  }
-
-  /**
-   * @return \Drupal\Core\Database\Connection
-   */
-  protected function getDatabase($database_contents) {
-    $database = $this->getMockBuilder('Drupal\Core\Database\Connection')
-      ->disableOriginalConstructor()
-      ->getMock();
-    $database->databaseContents = &$database_contents;
-    $database->expects($this->any())
-      ->method('select')->will($this->returnCallback(function ($base_table, $base_alias) use ($database_contents) {
-      return new FakeSelect($base_table, $base_alias, $database_contents);
-    }));
-    $database->expects($this->any())
-      ->method('schema')
-      ->will($this->returnCallback(function () use (&$database_contents) {
-      return new FakeDatabaseSchema($database_contents);
-    }));
-    $database->expects($this->any())
-      ->method('insert')
-      ->will($this->returnCallback(function ($table) use (&$database_contents) {
-      return new FakeInsert($database_contents, $table);
-    }));
-    $database->expects($this->any())
-      ->method('update')
-      ->will($this->returnCallback(function ($table) use (&$database_contents) {
-      return new FakeUpdate($database_contents, $table);
-    }));
-    $database->expects($this->any())
-      ->method('merge')
-      ->will($this->returnCallback(function ($table) use (&$database_contents) {
-      return new FakeMerge($database_contents, $table);
-    }));
-    $database->expects($this->any())
-      ->method('query')
-      ->will($this->throwException(new \Exception('Query is not supported')));
-    return $database;
-  }
-
-  /**
-   * Tests a query
-   *
-   * @param array|\Traversable
-   *   The countable. foreach-able actual results if a query is being run.
-   */
-  public function queryResultTest($iter, $expected_results) {
-    $this->assertSame(count($expected_results), count($iter), 'Number of results match');
-    $count = 0;
-    foreach ($iter as $data_row) {
-      $expected_row = $expected_results[$count];
-      $count++;
-      foreach ($expected_row as $key => $expected_value) {
-        $this->retrievalAssertHelper($expected_value, $this->getValue($data_row, $key), sprintf('Value matches for key "%s"', $key));
-      }
-    }
-    $this->assertSame(count($expected_results), $count);
-  }
-
-  /**
-   * @param array $row
-   * @param string $key
-   * @return mixed
-   */
-  protected function getValue($row, $key) {
-    return $row[$key];
-  }
-
-  /**
-   * Asserts tested values during test retrieval.
-   *
-   * @param mixed $expected_value
-   *   The incoming expected value to test.
-   * @param mixed $actual_value
-   *   The incoming value itself.
-   * @param string $message
-   *   The tested result as a formatted string.
-   */
-  protected function retrievalAssertHelper($expected_value, $actual_value, $message) {
-    if (is_array($expected_value)) {
-      foreach ($expected_value as $k => $v) {
-        $this->retrievalAssertHelper($v, $actual_value[$k], $message . '['. $k . ']');
-      }
-    }
-    else {
-      $this->assertSame((string) $expected_value, (string) $actual_value, $message);
-    }
-  }
-
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/TestSource.php b/core/modules/migrate/tests/Drupal/migrate/Tests/TestSource.php
deleted file mode 100644
index 99988d6..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/TestSource.php
+++ /dev/null
@@ -1,18 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\TestSource.
- */
-
-
-namespace Drupal\migrate\Tests;
-
-use Drupal\Core\Cache\CacheBackendInterface;
-use Drupal\migrate\Source;
-
-class TestSource extends Source {
-  function setCache(CacheBackendInterface $cache) {
-    $this->cache = $cache;
-  }
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/process/GetTest.php b/core/modules/migrate/tests/Drupal/migrate/Tests/process/GetTest.php
deleted file mode 100644
index e49e1f2..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/process/GetTest.php
+++ /dev/null
@@ -1,90 +0,0 @@
-<?php
-/**
- * @file
- * Contains
- */
-
-namespace Drupal\migrate\Tests\process;
-
-use Drupal\migrate\Plugin\migrate\process\TestGet;
-
-/**
- * @group migrate
- * @group Drupal
- */
-class GetTest extends MigrateProcessTestCase {
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'Get process plugin',
-      'description' => 'Tests the get process plugin.',
-      'group' => 'Migrate',
-    );
-  }
-
-  function setUp() {
-    $this->plugin = new TestGet();
-    parent::setUp();
-  }
-
-  function testTransformSourceString() {
-    $this->row->expects($this->once())
-      ->method('getSourceProperty')
-      ->with('test')
-      ->will($this->returnValue('source_value'));
-    $this->plugin->setSource('test');
-    $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'source_value');
-  }
-
-  function testTransformSourceArray() {
-    $map = array(
-      'test1' => 'source_value1',
-      'test2' => 'source_value2',
-    );
-    $this->plugin->setSource(array('test1', 'test2'));
-    $this->row->expects($this->exactly(2))
-      ->method('getSourceProperty')
-      ->will($this->returnCallback(function ($argument)  use ($map) { return $map[$argument]; } ));
-    $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, array('source_value1', 'source_value2'));
-  }
-
-  function testTransformSourceStringAt() {
-    $this->row->expects($this->once())
-      ->method('getSourceProperty')
-      ->with('@test')
-      ->will($this->returnValue('source_value'));
-    $this->plugin->setSource('@@test');
-    $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, 'source_value');
-  }
-
-  function testTransformSourceArrayAt() {
-    $map = array(
-      'test1' => 'source_value1',
-      '@test2' => 'source_value2',
-      '@test3' => 'source_value3',
-      'test4' => 'source_value4',
-    );
-    $this->plugin->setSource(array('test1', '@@test2', '@@test3', 'test4'));
-    $this->row->expects($this->exactly(4))
-      ->method('getSourceProperty')
-      ->will($this->returnCallback(function ($argument)  use ($map) { return $map[$argument]; } ));
-    $value = $this->plugin->transform(NULL, $this->migrateExecutable, $this->row, 'destinationproperty');
-    $this->assertSame($value, array('source_value1', 'source_value2', 'source_value3', 'source_value4'));
-  }
-}
-
-namespace Drupal\migrate\Plugin\migrate\process;
-
-class TestGet extends Get {
-  function __construct() {
-  }
-  function setSource($source) {
-    $this->configuration['source'] = $source;
-  }
-}
diff --git a/core/modules/migrate/tests/Drupal/migrate/Tests/process/MigrateProcessTestCase.php b/core/modules/migrate/tests/Drupal/migrate/Tests/process/MigrateProcessTestCase.php
deleted file mode 100644
index d99a865..0000000
--- a/core/modules/migrate/tests/Drupal/migrate/Tests/process/MigrateProcessTestCase.php
+++ /dev/null
@@ -1,39 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate\Tests\process\MigrateProcessTestCase.
- */
-
-namespace Drupal\migrate\Tests\process;
-
-use Drupal\migrate\Tests\MigrateTestCase;
-
-abstract class MigrateProcessTestCase extends MigrateTestCase {
-
-  /**
-   * @var \Drupal\migrate\Plugin\migrate\process\TestGet
-   */
-  protected $plugin;
-
-  /**
-   * @var \Drupal\migrate\Row
-   */
-  protected $row;
-
-  /**
-   * @var \Drupal\migrate\MigrateExecutable
-   */
-  protected $migrateExecutable;
-
-  function setUp() {
-    $this->row = $this->getMockBuilder('Drupal\migrate\Row')
-      ->disableOriginalConstructor()
-      ->getMock();
-    $this->migrateExecutable = $this->getMockBuilder('Drupal\migrate\MigrateExecutable')
-      ->disableOriginalConstructor()
-      ->getMock();
-    parent::setUp();
-  }
-
-}
diff --git a/core/modules/node/lib/Drupal/node/Plugin/Search/NodeSearch.php b/core/modules/node/lib/Drupal/node/Plugin/Search/NodeSearch.php
index 0dbd1ac..da32b99 100644
--- a/core/modules/node/lib/Drupal/node/Plugin/Search/NodeSearch.php
+++ b/core/modules/node/lib/Drupal/node/Plugin/Search/NodeSearch.php
@@ -14,7 +14,7 @@
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Language\Language;
 use Drupal\Core\Plugin\PluginFormInterface;
 use Drupal\Core\Session\AccountInterface;
@@ -68,7 +68,7 @@ class NodeSearch extends SearchPluginBase implements AccessibleInterface, Search
   /**
    * The Drupal state object used to set 'node.cron_last'.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -111,7 +111,7 @@ static public function create(ContainerInterface $container, array $configuratio
       $container->get('plugin.manager.entity'),
       $container->get('module_handler'),
       $container->get('config.factory')->get('search.settings'),
-      $container->get('keyvalue')->get('state'),
+      $container->get('state'),
       $container->get('current_user')
     );
   }
@@ -133,12 +133,12 @@ static public function create(ContainerInterface $container, array $configuratio
    *   A module manager object.
    * @param \Drupal\Core\Config\Config $search_settings
    *   A config object for 'search.settings'.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The Drupal state object used to set 'node.cron_last'.
    * @param \Drupal\Core\Session\AccountInterface $account
    *   The $account object to use for checking for access to advanced search.
    */
-  public function __construct(array $configuration, $plugin_id, array $plugin_definition, Connection $database, EntityManagerInterface $entity_manager, ModuleHandlerInterface $module_handler, Config $search_settings, KeyValueStoreInterface $state, AccountInterface $account = NULL) {
+  public function __construct(array $configuration, $plugin_id, array $plugin_definition, Connection $database, EntityManagerInterface $entity_manager, ModuleHandlerInterface $module_handler, Config $search_settings, StateInterface $state, AccountInterface $account = NULL) {
     $this->database = $database;
     $this->entityManager = $entity_manager;
     $this->moduleHandler = $module_handler;
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeTypePersistenceTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeTypePersistenceTest.php
index 66ea769..f07f3e1 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeTypePersistenceTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeTypePersistenceTest.php
@@ -55,6 +55,7 @@ function testNodeTypeCustomizationPersistence() {
     $this->drupalPostForm('admin/modules/uninstall', $edit, t('Uninstall'));
     $this->drupalPostForm(NULL, array(), t('Uninstall'));
     $forum = entity_load('node_type', 'forum');
+    \Drupal::state()->resetCache();
     $this->assertFalse($forum->isLocked(), 'Forum node type is not locked');
     $this->drupalGet('node/add');
     $this->assertNoText('forum', 'forum type is no longer found on node/add');
diff --git a/core/modules/node/node.views.inc b/core/modules/node/node.views.inc
index cdeb8a0..6c82604 100644
--- a/core/modules/node/node.views.inc
+++ b/core/modules/node/node.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for node.module.
+ * Provide views data and handlers for node.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 use Drupal\views\Analyzer;
diff --git a/core/modules/rest/lib/Drupal/rest/Plugin/views/display/RestExport.php b/core/modules/rest/lib/Drupal/rest/Plugin/views/display/RestExport.php
index 19bc077..cef8953 100644
--- a/core/modules/rest/lib/Drupal/rest/Plugin/views/display/RestExport.php
+++ b/core/modules/rest/lib/Drupal/rest/Plugin/views/display/RestExport.php
@@ -8,7 +8,7 @@
 namespace Drupal\rest\Plugin\views\display;
 
 
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Routing\RouteProviderInterface;
 use Drupal\views\Annotation\ViewsDisplay;
 use Drupal\Core\Annotation\Translation;
@@ -99,14 +99,14 @@ class RestExport extends PathPluginBase {
    *   The plugin implementation definition.
    * @param \Drupal\Core\Routing\RouteProviderInterface $route_provider
    *   The route provider
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state key value store.
    * @param \Drupal\Core\ContentNegotiation $content_negotiation
    *   The content negotiation library.
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   The request object.
    */
-  public function __construct(array $configuration, $plugin_id, array $plugin_definition, RouteProviderInterface $route_provider, KeyValueStoreInterface $state, ContentNegotiation $content_negotiation, Request $request) {
+  public function __construct(array $configuration, $plugin_id, array $plugin_definition, RouteProviderInterface $route_provider, StateInterface $state, ContentNegotiation $content_negotiation, Request $request) {
     parent::__construct($configuration, $plugin_id, $plugin_definition, $route_provider, $state);
     $this->contentNegotiation = $content_negotiation;
     $this->request = $request;
diff --git a/core/modules/rest/tests/Drupal/rest/Tests/CollectRoutesTest.php b/core/modules/rest/tests/Drupal/rest/Tests/CollectRoutesTest.php
index ae4bb43..05c6d5d 100644
--- a/core/modules/rest/tests/Drupal/rest/Tests/CollectRoutesTest.php
+++ b/core/modules/rest/tests/Drupal/rest/Tests/CollectRoutesTest.php
@@ -82,7 +82,7 @@ protected function setUp() {
       ->getMock();
     $container->set('router.route_provider', $route_provider);
 
-    $state = $this->getMock('\Drupal\Core\KeyValueStore\KeyValueStoreInterface');
+    $state = $this->getMock('\Drupal\Core\KeyValueStore\StateInterface');
     $container->set('state', $state);
 
     $style_manager = $this->getMockBuilder('\Drupal\views\Plugin\ViewsPluginManager')
diff --git a/core/modules/search/lib/Drupal/search/Form/SearchSettingsForm.php b/core/modules/search/lib/Drupal/search/Form/SearchSettingsForm.php
index 0bf795a..5e280ee 100644
--- a/core/modules/search/lib/Drupal/search/Form/SearchSettingsForm.php
+++ b/core/modules/search/lib/Drupal/search/Form/SearchSettingsForm.php
@@ -9,7 +9,7 @@
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Config\Context\ContextInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Plugin\PluginFormInterface;
 use Drupal\search\SearchPluginManager;
 use Drupal\Core\Form\ConfigFormBase;
@@ -44,7 +44,7 @@ class SearchSettingsForm extends ConfigFormBase {
   /**
    * The Drupal state storage service.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -59,10 +59,10 @@ class SearchSettingsForm extends ConfigFormBase {
    *   The manager for search plugins.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state key/value store interface, gives access to state based config settings.
    */
-  public function __construct(ConfigFactory $config_factory, ContextInterface $context, SearchPluginManager $manager, ModuleHandlerInterface $module_handler, KeyValueStoreInterface $state) {
+  public function __construct(ConfigFactory $config_factory, ContextInterface $context, SearchPluginManager $manager, ModuleHandlerInterface $module_handler, StateInterface $state) {
     parent::__construct($config_factory, $context);
     $this->searchSettings = $config_factory->get('search.settings');
     $this->searchPluginManager = $manager;
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
index 5eb5b26..dee1760 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
@@ -175,10 +175,8 @@ public function containerBuild(ContainerBuilder $container) {
         ->addArgument(new Reference('service_container'))
         ->addArgument(new Reference('settings'));
 
-      $container->register('state', 'Drupal\Core\KeyValueStore\KeyValueStoreInterface')
-        ->setFactoryService(new Reference('keyvalue'))
-        ->setFactoryMethod('get')
-        ->addArgument('state');
+      $container->register('state', 'Drupal\Core\KeyValueStore\State')
+        ->addArgument(new Reference('keyvalue'));
     }
 
     if ($container->hasDefinition('path_processor_alias')) {
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index 284df1d..e26b53b 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -2445,6 +2445,7 @@ protected function drupalGetSettings() {
    *   An array containing e-mail messages captured during the current test.
    */
   protected function drupalGetMails($filter = array()) {
+    \Drupal::state()->resetCache();
     $captured_emails = \Drupal::state()->get('system.test_email_collector') ?: array();
     $filtered_emails = array();
 
@@ -3442,6 +3443,7 @@ protected function assertNoResponse($code, $message = '', $group = 'Browser') {
    *   TRUE on pass, FALSE on fail.
    */
   protected function assertMail($name, $value = '', $message = '', $group = 'E-mail') {
+    \Drupal::state()->resetCache();
     $captured_emails = \Drupal::state()->get('system.test_email_collector') ?: array();
     $email = end($captured_emails);
     return $this->assertTrue($email && isset($email[$name]) && $email[$name] == $value, $message, $group);
diff --git a/core/modules/statistics/statistics.views.inc b/core/modules/statistics/statistics.views.inc
index fe9a9e6..3814692 100644
--- a/core/modules/statistics/statistics.views.inc
+++ b/core/modules/statistics/statistics.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for statistics.module.
+ * Provide views data and handlers for statistics.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/system/lib/Drupal/system/Form/CronForm.php b/core/modules/system/lib/Drupal/system/Form/CronForm.php
index 84dddb1..5d94762 100644
--- a/core/modules/system/lib/Drupal/system/Form/CronForm.php
+++ b/core/modules/system/lib/Drupal/system/Form/CronForm.php
@@ -9,7 +9,7 @@
 
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Config\Context\ContextInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Form\ConfigFormBase;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\RedirectResponse;
@@ -22,7 +22,7 @@ class CronForm extends ConfigFormBase {
   /**
    * Stores the state storage service.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -33,10 +33,10 @@ class CronForm extends ConfigFormBase {
    *   The factory for configuration objects.
    * @param \Drupal\Core\Config\Context\ContextInterface $context
    *   The configuration context used for this configuration object.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state key value store.
    */
-  public function __construct(ConfigFactory $config_factory, ContextInterface $context, KeyValueStoreInterface $state) {
+  public function __construct(ConfigFactory $config_factory, ContextInterface $context, StateInterface $state) {
     parent::__construct($config_factory, $context);
     $this->state = $state;
   }
diff --git a/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php b/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
index fa10960..693dc28 100644
--- a/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
+++ b/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
@@ -9,7 +9,7 @@
 
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Config\Context\ContextInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Form\ConfigFormBase;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
@@ -21,7 +21,7 @@ class SiteMaintenanceModeForm extends ConfigFormBase {
   /**
    * The state keyvalue collection.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -32,10 +32,10 @@ class SiteMaintenanceModeForm extends ConfigFormBase {
    *   The factory for configuration objects.
    * @param \Drupal\Core\Config\Context\ContextInterface $context
    *   The configuration context to use.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state keyvalue collection to use.
    */
-  public function __construct(ConfigFactory $config_factory, ContextInterface $context, KeyValueStoreInterface $state) {
+  public function __construct(ConfigFactory $config_factory, ContextInterface $context, StateInterface $state) {
     parent::__construct($config_factory, $context);
     $this->state = $state;
   }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Batch/ProcessingTest.php b/core/modules/system/lib/Drupal/system/Tests/Batch/ProcessingTest.php
index de63b73..0008e5f 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Batch/ProcessingTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Batch/ProcessingTest.php
@@ -54,6 +54,7 @@ function testBatchForm() {
     $edit = array('batch' => 'batch_1');
     $this->drupalPostForm('batch-test', $edit, 'Submit');
     $this->assertBatchMessages($this->_resultMessages('batch_1'), 'Batch with simple operations performed successfully.');
+    \Drupal::state()->resetCache();
     $this->assertEqual(batch_test_stack(), $this->_resultStack('batch_1'), 'Execution order was correct.');
     $this->assertText('Redirection successful.', 'Redirection after batch execution is correct.');
 
@@ -61,6 +62,7 @@ function testBatchForm() {
     $edit = array('batch' => 'batch_2');
     $this->drupalPostForm('batch-test', $edit, 'Submit');
     $this->assertBatchMessages($this->_resultMessages('batch_2'), 'Batch with multistep operation performed successfully.');
+    \Drupal::state()->resetCache();
     $this->assertEqual(batch_test_stack(), $this->_resultStack('batch_2'), 'Execution order was correct.');
     $this->assertText('Redirection successful.', 'Redirection after batch execution is correct.');
 
@@ -68,6 +70,7 @@ function testBatchForm() {
     $edit = array('batch' => 'batch_3');
     $this->drupalPostForm('batch-test', $edit, 'Submit');
     $this->assertBatchMessages($this->_resultMessages('batch_3'), 'Batch with simple and multistep operations performed successfully.');
+    \Drupal::state()->resetCache();
     $this->assertEqual(batch_test_stack(), $this->_resultStack('batch_3'), 'Execution order was correct.');
     $this->assertText('Redirection successful.', 'Redirection after batch execution is correct.');
 
@@ -75,6 +78,7 @@ function testBatchForm() {
     $edit = array('batch' => 'batch_4');
     $this->drupalPostForm('batch-test', $edit, 'Submit');
     $this->assertBatchMessages($this->_resultMessages('batch_4'), 'Nested batch performed successfully.');
+    \Drupal::state()->resetCache();
     $this->assertEqual(batch_test_stack(), $this->_resultStack('batch_4'), 'Execution order was correct.');
     $this->assertText('Redirection successful.', 'Redirection after batch execution is correct.');
   }
@@ -95,6 +99,7 @@ function testBatchFormMultistep() {
     // Second step triggers batch 2.
     $this->drupalPostForm(NULL, array(), 'Submit');
     $this->assertBatchMessages($this->_resultMessages('batch_2'), 'Batch for step 2 performed successfully.');
+    \Drupal::state()->resetCache();
     $this->assertEqual(batch_test_stack(), $this->_resultStack('batch_2'), 'Execution order was correct.');
     $this->assertText('Redirection successful.', 'Redirection after batch execution is correct.');
   }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTranslationFormTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTranslationFormTest.php
index 78326e9..18dc465 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTranslationFormTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTranslationFormTest.php
@@ -113,6 +113,7 @@ function testEntityFormLanguage() {
     $node->getTranslation($langcode2)->body->value = $this->randomName(16);
     $node->save();
     $this->drupalGet($langcode2 . '/node/' . $node->id() . '/edit');
+    \Drupal::state()->resetCache();
     $form_langcode = \Drupal::state()->get('entity_test.form_langcode') ?: FALSE;
     $this->assertTrue($langcode2 == $form_langcode, "Node edit form language is $langcode2.");
   }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityUnitTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityUnitTestBase.php
index 3391a14..ccf6070 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityUnitTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityUnitTestBase.php
@@ -32,7 +32,7 @@
   /**
    * The state service.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php b/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
index 409f3aa..ee61284 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
@@ -93,6 +93,7 @@ function testCustom403And404Pages() {
 
       // Check that the initial trail (during the Drupal bootstrap) matches
       // what we expect.
+      \Drupal::state()->resetCache();
       $initial_trail = \Drupal::state()->get('menu_test.active_trail_initial') ?: array();
       $this->assertEqual(count($initial_trail), count($expected_trail[$status_code]['initial']), format_string('The initial active trail for a @status_code page contains the expected number of items (expected: @expected, found: @found).', array(
         '@status_code' => $status_code,
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/CronRunTest.php b/core/modules/system/lib/Drupal/system/Tests/System/CronRunTest.php
index 6fe28f2..996dea4 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/CronRunTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/CronRunTest.php
@@ -68,6 +68,7 @@ function testAutomaticCron() {
     \Drupal::state()->set('system.cron_last', $cron_last);
     $this->drupalGet('');
     sleep(1);
+    \Drupal::state()->resetCache();
     $this->assertTrue($cron_last < \Drupal::state()->get('system.cron_last'), 'Cron runs when the cron threshold is passed.');
 
     // Disable the cron threshold through the interface.
diff --git a/core/modules/system/tests/modules/entity_test/entity_test.views.inc b/core/modules/system/tests/modules/entity_test/entity_test.views.inc
index 389923a..32da74d 100644
--- a/core/modules/system/tests/modules/entity_test/entity_test.views.inc
+++ b/core/modules/system/tests/modules/entity_test/entity_test.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for entity_test.module.
+ * Provide views data and handlers for entity_test.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/EventSubscriber/ActiveTrailSubscriber.php b/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/EventSubscriber/ActiveTrailSubscriber.php
index 4bb3595..5b63e55 100644
--- a/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/EventSubscriber/ActiveTrailSubscriber.php
+++ b/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/EventSubscriber/ActiveTrailSubscriber.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\menu_test\EventSubscriber;
 
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpKernel\Event\GetResponseEvent;
 use Symfony\Component\HttpKernel\KernelEvents;
@@ -27,17 +27,17 @@ class ActiveTrailSubscriber implements EventSubscriberInterface {
   /**
    * The state service.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
   /**
    * Constructs a new ActiveTrailSubscriber.
    *
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state service.
    */
-  public function __construct(KeyValueStoreInterface $state) {
+  public function __construct(StateInterface $state) {
     $this->state = $state;
   }
 
diff --git a/core/modules/system/tests/modules/service_provider_test/lib/Drupal/service_provider_test/TestClass.php b/core/modules/system/tests/modules/service_provider_test/lib/Drupal/service_provider_test/TestClass.php
index 1c8ea06..9078493 100644
--- a/core/modules/system/tests/modules/service_provider_test/lib/Drupal/service_provider_test/TestClass.php
+++ b/core/modules/system/tests/modules/service_provider_test/lib/Drupal/service_provider_test/TestClass.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\service_provider_test;
 
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\DestructableInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpKernel\Event\GetResponseEvent;
@@ -18,17 +18,17 @@ class TestClass implements EventSubscriberInterface, DestructableInterface {
   /**
    * The state keyvalue collection.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
   /**
    * Constructor.
    *
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state key value store.
    */
-  public function __construct(KeyValueStoreInterface $state) {
+  public function __construct(StateInterface $state) {
     $this->state = $state;
   }
 
diff --git a/core/modules/taxonomy/taxonomy.pages.inc b/core/modules/taxonomy/taxonomy.pages.inc
index 96f84aa..fb88184 100644
--- a/core/modules/taxonomy/taxonomy.pages.inc
+++ b/core/modules/taxonomy/taxonomy.pages.inc
@@ -24,23 +24,11 @@ function taxonomy_term_page(Term $term) {
   foreach ($term->uriRelationships() as $rel) {
     $uri = $term->uri($rel);
     // Set the term path as the canonical URL to prevent duplicate content.
-    $build['#attached']['drupal_add_html_head_link'][] = array(
-      array(
-        'rel' => $rel,
-        'href' => url($uri['path'], $uri['options']),
-      ),
-      TRUE,
-    );
+    drupal_add_html_head_link(array('rel' => $rel, 'href' => url($uri['path'], $uri['options'])), TRUE);
 
     if ($rel == 'canonical') {
       // Set the non-aliased canonical path as a default shortlink.
-      $build['#attached']['drupal_add_html_head_link'][] = array(
-        array(
-          'rel' => 'shortlink',
-          'href' => url($uri['path'], array_merge($uri['options'], array('alias' => TRUE))),
-        ),
-        TRUE,
-      );
+      drupal_add_html_head_link(array('rel' => 'shortlink', 'href' => url($uri['path'], array_merge($uri['options'], array('alias' => TRUE)))), TRUE);
     }
   }
 
diff --git a/core/modules/taxonomy/taxonomy.views.inc b/core/modules/taxonomy/taxonomy.views.inc
index 3404b3a..001c125 100644
--- a/core/modules/taxonomy/taxonomy.views.inc
+++ b/core/modules/taxonomy/taxonomy.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for taxonomy.module.
+ * Provide views data and handlers for taxonomy.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 use Drupal\Core\Entity\FieldableDatabaseStorageController;
diff --git a/core/modules/tracker/tracker.views.inc b/core/modules/tracker/tracker.views.inc
index 14c125e..1a5e1fb 100644
--- a/core/modules/tracker/tracker.views.inc
+++ b/core/modules/tracker/tracker.views.inc
@@ -3,6 +3,8 @@
 /**
  * @file
  * Provide views data for tracker.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/user/user.views.inc b/core/modules/user/user.views.inc
index 52d28eb..f49e812 100644
--- a/core/modules/user/user.views.inc
+++ b/core/modules/user/user.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data for user.module.
+ * Provide views data and handlers for user.module.
+ *
+ * @ingroup views_module_handlers
  */
 
 use Drupal\views\ViewExecutable;
diff --git a/core/modules/views/lib/Drupal/views/EventSubscriber/RouteSubscriber.php b/core/modules/views/lib/Drupal/views/EventSubscriber/RouteSubscriber.php
index 26108b9..c8b0437 100644
--- a/core/modules/views/lib/Drupal/views/EventSubscriber/RouteSubscriber.php
+++ b/core/modules/views/lib/Drupal/views/EventSubscriber/RouteSubscriber.php
@@ -10,7 +10,7 @@
 use Drupal\Component\Utility\MapArray;
 use Drupal\Core\DestructableInterface;
 use Drupal\Core\Entity\EntityManagerInterface;
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Routing\RouteSubscriberBase;
 use Drupal\views\Plugin\views\display\DisplayRouterInterface;
 use Drupal\views\ViewExecutable;
@@ -44,7 +44,7 @@ class RouteSubscriber extends RouteSubscriberBase implements DestructableInterfa
   /**
    * The state key value store.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -60,10 +60,10 @@ class RouteSubscriber extends RouteSubscriberBase implements DestructableInterfa
    *
    * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
    *   The entity manager.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state key value store.
    */
-  public function __construct(EntityManagerInterface $entity_manager, KeyValueStoreInterface $state) {
+  public function __construct(EntityManagerInterface $entity_manager, StateInterface $state) {
     $this->viewStorageController = $entity_manager->getStorageController('view');
     $this->state = $state;
   }
diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/display/PathPluginBase.php b/core/modules/views/lib/Drupal/views/Plugin/views/display/PathPluginBase.php
index 51c8308..0fa04f8 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/display/PathPluginBase.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/display/PathPluginBase.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\views\Plugin\views\display;
 
-use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Routing\RouteCompiler;
 use Drupal\Core\Routing\RouteProviderInterface;
 use Drupal\views\Views;
@@ -35,7 +35,7 @@
   /**
    * The state key value store.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
   protected $state;
 
@@ -50,10 +50,10 @@
    *   The plugin implementation definition.
    * @param \Drupal\Core\Routing\RouteProviderInterface $route_provider
    *   The route provider.
-   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The state key value store.
    */
-  public function __construct(array $configuration, $plugin_id, array $plugin_definition, RouteProviderInterface $route_provider, KeyValueStoreInterface $state) {
+  public function __construct(array $configuration, $plugin_id, array $plugin_definition, RouteProviderInterface $route_provider, StateInterface $state) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
 
     $this->routeProvider = $route_provider;
diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/style/Rss.php b/core/modules/views/lib/Drupal/views/Plugin/views/style/Rss.php
index 136e5bb..7b1e0b1 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/style/Rss.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/style/Rss.php
@@ -57,13 +57,13 @@ public function attachTo($display_id, $path, $title) {
         '#url' => $url,
         '#title' => $title,
       );
-      $feed_icon['#attached']['drupal_add_html_head_link'][][] = array(
+      $this->view->feed_icon .= drupal_render($feed_icon);
+      drupal_add_html_head_link(array(
         'rel' => 'alternate',
         'type' => 'application/rss+xml',
         'title' => $title,
-        'href' => $url,
-      );
-      $this->view->feed_icon .= drupal_render($feed_icon);
+        'href' => $url
+      ));
     }
   }
 
diff --git a/core/modules/views/tests/Drupal/views/Tests/EventSubscriber/RouteSubscriberTest.php b/core/modules/views/tests/Drupal/views/Tests/EventSubscriber/RouteSubscriberTest.php
index 8a69bd3..6e4c644 100644
--- a/core/modules/views/tests/Drupal/views/Tests/EventSubscriber/RouteSubscriberTest.php
+++ b/core/modules/views/tests/Drupal/views/Tests/EventSubscriber/RouteSubscriberTest.php
@@ -44,7 +44,7 @@ class RouteSubscriberTest extends UnitTestCase {
   /**
    * The mocked key value storage.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\KeyValueStore\StateInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $state;
 
@@ -68,7 +68,7 @@ protected function setUp() {
       ->method('getStorageController')
       ->with('view')
       ->will($this->returnValue($this->viewStorageController));
-    $this->state = $this->getMock('\Drupal\Core\KeyValueStore\KeyValueStoreInterface');
+    $this->state = $this->getMock('\Drupal\Core\KeyValueStore\StateInterface');
     $this->routeSubscriber = new TestRouteSubscriber($this->entityManager, $this->state);
   }
 
diff --git a/core/modules/views/tests/Drupal/views/Tests/Plugin/display/PathPluginBaseTest.php b/core/modules/views/tests/Drupal/views/Tests/Plugin/display/PathPluginBaseTest.php
index 2e2395e..748d3c3 100644
--- a/core/modules/views/tests/Drupal/views/Tests/Plugin/display/PathPluginBaseTest.php
+++ b/core/modules/views/tests/Drupal/views/Tests/Plugin/display/PathPluginBaseTest.php
@@ -43,7 +43,7 @@ class PathPluginBaseTest extends UnitTestCase {
   /**
    * The mocked key value storage.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\KeyValueStore\StateInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $state;
 
@@ -62,7 +62,7 @@ protected function setUp() {
     parent::setUp();
 
     $this->routeProvider = $this->getMock('Drupal\Core\Routing\RouteProviderInterface');
-    $this->state = $this->getMock('\Drupal\Core\KeyValueStore\KeyValueStoreInterface');
+    $this->state = $this->getMock('\Drupal\Core\KeyValueStore\StateInterface');
     $this->pathPlugin = $this->getMockBuilder('Drupal\views\Plugin\views\display\PathPluginBase')
       ->setConstructorArgs(array(array(), 'path_base', array(), $this->routeProvider, $this->state))
       ->setMethods(NULL)
diff --git a/core/modules/views/views.api.php b/core/modules/views/views.api.php
index a1fa531..ea2c97c 100644
--- a/core/modules/views/views.api.php
+++ b/core/modules/views/views.api.php
@@ -839,3 +839,11 @@ function hook_views_plugins_wizard_alter(array &$plugins) {
 /**
  * @}
  */
+
+/**
+ * @defgroup views_module_handlers Views module handlers
+ * @{
+ * Handlers exposed by various modules to Views.
+ * @}
+ */
+
diff --git a/core/modules/views/views.views.inc b/core/modules/views/views.views.inc
index edf844a..b3af1d4 100644
--- a/core/modules/views/views.views.inc
+++ b/core/modules/views/views.views.inc
@@ -2,7 +2,9 @@
 
 /**
  * @file
- * Provide views data that isn't tied to any other module.
+ * Provide views data and handlers that aren't tied to any other module.
+ *
+ * @ingroup views_module_handlers
  */
 
 /**
diff --git a/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewListControllerTest.php b/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewListControllerTest.php
index b30bb34..12a0984 100644
--- a/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewListControllerTest.php
+++ b/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewListControllerTest.php
@@ -77,7 +77,7 @@ public function testBuildRowEntityList() {
       array(array(), 'default', $display_manager->getDefinition('default'))
     );
     $route_provider = $this->getMock('Drupal\Core\Routing\RouteProviderInterface');
-    $state = $this->getMock('\Drupal\Core\KeyValueStore\KeyValueStoreInterface');
+    $state = $this->getMock('\Drupal\Core\KeyValueStore\StateInterface');
     $page_display = $this->getMock('Drupal\views\Plugin\views\display\Page',
       array('initDisplay', 'getPath'),
       array(array(), 'default', $display_manager->getDefinition('page'), $route_provider, $state)
diff --git a/core/tests/Drupal/Tests/Core/Asset/CssCollectionRendererUnitTest.php b/core/tests/Drupal/Tests/Core/Asset/CssCollectionRendererUnitTest.php
index bfbe65c..fecb135 100644
--- a/core/tests/Drupal/Tests/Core/Asset/CssCollectionRendererUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Asset/CssCollectionRendererUnitTest.php
@@ -66,7 +66,7 @@ class CssCollectionRendererUnitTest extends UnitTestCase {
   /**
    * The state mock class.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\KeyValueStore\StateInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $state;
 
@@ -81,7 +81,7 @@ public static function getInfo() {
   function setUp() {
     parent::setUp();
 
-    $this->state = $this->getMock('Drupal\Core\KeyValueStore\KeyValueStoreInterface');
+    $this->state = $this->getMock('Drupal\Core\KeyValueStore\StateInterface');
 
     $this->renderer = new CssCollectionRenderer($this->state);
     $this->file_css_group = array(
diff --git a/core/tests/Drupal/Tests/Core/PrivateKeyTest.php b/core/tests/Drupal/Tests/Core/PrivateKeyTest.php
index a77a939..9f864f8 100644
--- a/core/tests/Drupal/Tests/Core/PrivateKeyTest.php
+++ b/core/tests/Drupal/Tests/Core/PrivateKeyTest.php
@@ -19,7 +19,7 @@ class PrivateKeyTest extends UnitTestCase {
   /**
    * The state mock class.
    *
-   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\KeyValueStore\StateInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $state;
 
@@ -52,7 +52,7 @@ public function setUp() {
     parent::setUp();
     $this->key = Crypt::randomStringHashed(55);
 
-    $this->state = $this->getMock('Drupal\Core\KeyValueStore\KeyValueStoreInterface');
+    $this->state = $this->getMock('Drupal\Core\KeyValueStore\StateInterface');
 
     $this->privateKey = new PrivateKey($this->state);
   }
diff --git a/core/themes/bartik/css/style.css b/core/themes/bartik/css/style.css
index 6314e93..5dad110 100644
--- a/core/themes/bartik/css/style.css
+++ b/core/themes/bartik/css/style.css
@@ -953,17 +953,17 @@ ul.links {
 
 /* ------------------ Footer ------------------ */
 
-#footer-wrapper .block .content {
+#footer-wrapper {
   color: #c0c0c0;
   color: rgba(255, 255, 255, 0.65);
   font-size: 0.857em;
 }
-#footer-wrapper .block .content a {
+#footer-wrapper a {
   color: #fcfcfc;
   color: rgba(255, 255, 255, 0.8);
 }
-#footer-wrapper .block .content a:hover,
-#footer-wrapper .block .content a:focus {
+#footer-wrapper a:hover,
+#footer-wrapper a:focus {
   color: #fefefe;
   color: rgba(255, 255, 255, 0.95);
   text-decoration: underline;