diff --git a/core/INSTALL.txt b/core/INSTALL.txt
index 6ae05b4..79c08bd 100644
--- a/core/INSTALL.txt
+++ b/core/INSTALL.txt
@@ -18,7 +18,7 @@ Drupal requires:
 - A web server with PHP support, for example:
   - Apache 2.0 (or greater) (http://httpd.apache.org/).
   - Nginx 1.1 (or greater) (http://nginx.com/).
-- PHP 5.4.5 (or greater) (http://php.net/). For better security support it is
+- PHP 5.4.5 (or greater) (http://php.net/). For better security support its
   recommended to update to at least 5.5.21 or 5.6.5.
 - One of the following databases:
   - MySQL 5.5.3 (or greater) (http://www.mysql.com/).
diff --git a/core/MAINTAINERS.txt b/core/MAINTAINERS.txt
index 7e6b0c7..c72d26b 100644
--- a/core/MAINTAINERS.txt
+++ b/core/MAINTAINERS.txt
@@ -371,7 +371,6 @@ REST module
 Responsive Image module
 - Peter Droogmans 'attiks' http://drupal.org/user/105002
 - Marc Drummond 'mdrummond' http://www.drupal.org/user/360968/
-- Jelle Sebreghts 'Jelle_S' https://www.drupal.org/user/829198
 
 Search module
 - Jennifer Hodgdon 'jhodgdon' https://drupal.org/user/155601
diff --git a/core/lib/Drupal/Component/Utility/SafeMarkup.php b/core/lib/Drupal/Component/Utility/SafeMarkup.php
index 15d5223..d69daa5 100644
--- a/core/lib/Drupal/Component/Utility/SafeMarkup.php
+++ b/core/lib/Drupal/Component/Utility/SafeMarkup.php
@@ -282,4 +282,37 @@ public static function placeholder($text) {
     return $string;
   }
 
+  /**
+   * Replace all occurrences of the search string with the replacement string.
+   *
+   * Functions identically to str_replace, but marks the returned output as safe
+   * if all the inputs and the subject have also been marked as safe.
+   */
+  public static function replace($search, $replace, $subject) {
+    $output = str_replace($search, $replace, $subject);
+
+    if (!is_array($replace)) {
+      if (!SafeMarkup::isSafe($replace)) {
+        return $output;
+      }
+    }
+    else {
+      foreach ($replace as $replacement) {
+        if (!SafeMarkup::isSafe($replacement)) {
+          return $output;
+        }
+      }
+    }
+
+    // If we have reached this point, then all replacements were safe, and
+    // therefore if the subject was also safe, then the entire output is also
+    // safe, and should be marked as such.
+    if (SafeMarkup::isSafe($subject)) {
+      return SafeMarkup::set($output);
+    }
+    else {
+      return $output;
+    }
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/CompositeConstraintBase.php b/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/CompositeConstraintBase.php
deleted file mode 100644
index 3c605dc..0000000
--- a/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/CompositeConstraintBase.php
+++ /dev/null
@@ -1,30 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase.
- */
-
-namespace Drupal\Core\Entity\Plugin\Validation\Constraint;
-
-use Symfony\Component\Validator\Constraint;
-
-/**
- * Provides a base class for constraints validating multiple fields.
- *
- * The constraint must be defined on entity-level; i.e., added to the entity
- * type.
- *
- * @see \Drupal\Core\Entity\EntityType::addConstraint
- */
-abstract class CompositeConstraintBase extends Constraint {
-
-  /**
-   * An array of entity fields which should be passed to the validator.
-   *
-   * @return string[]
-   *   An array of field names.
-   */
-  abstract public function coversFields();
-
-}
diff --git a/core/lib/Drupal/Core/Render/Element/HtmlTag.php b/core/lib/Drupal/Core/Render/Element/HtmlTag.php
index 553767f..6acd7ff 100644
--- a/core/lib/Drupal/Core/Render/Element/HtmlTag.php
+++ b/core/lib/Drupal/Core/Render/Element/HtmlTag.php
@@ -94,7 +94,7 @@ public static function preRenderHtmlTag($element) {
       $markup = SafeMarkup::set($markup);
     }
     if (!empty($element['#noscript'])) {
-      $element['#markup'] = '<noscript>' . $markup . '</noscript>';
+      $element['#markup'] = SafeMarkup::format('<noscript>!markup</noscript>', array('!markup' => $markup));
     }
     else {
       $element['#markup'] = $markup;
diff --git a/core/lib/Drupal/Core/Render/Renderer.php b/core/lib/Drupal/Core/Render/Renderer.php
index b969a51..c253ae6 100644
--- a/core/lib/Drupal/Core/Render/Renderer.php
+++ b/core/lib/Drupal/Core/Render/Renderer.php
@@ -245,9 +245,8 @@ protected function doRender(&$elements, $is_root_call = FALSE) {
       $elements['#children'] = '';
     }
 
-    // @todo Simplify after https://drupal.org/node/2273925
     if (isset($elements['#markup'])) {
-      $elements['#markup'] = SafeMarkup::set($elements['#markup']);
+      $elements['#markup'] = SafeMarkup::checkAdminXss($elements['#markup']);
     }
 
     // Assume that if #theme is set it represents an implemented hook.
@@ -545,7 +544,10 @@ public function generateCachePlaceholder($callback, array &$context) {
       'token' => Crypt::randomBytesBase64(55),
     ];
 
-    return '<drupal-render-cache-placeholder callback="' . $callback . '" token="' . $context['token'] . '"></drupal-render-cache-placeholder>';
+    return SafeMarkup::format('<drupal-render-cache-placeholder callback="@callback" token="@token"></drupal-render-cache-placeholder>', array(
+      '@callback' => $callback,
+      '@token' => $context['token'],
+    ));
   }
 
 }
diff --git a/core/modules/comment/src/CommentForm.php b/core/modules/comment/src/CommentForm.php
index 12f5bb8..9f47519 100644
--- a/core/modules/comment/src/CommentForm.php
+++ b/core/modules/comment/src/CommentForm.php
@@ -323,12 +323,9 @@ public function validate(array $form, FormStateInterface $form_state) {
     foreach ($violations as $violation) {
       $form_state->setErrorByName('date', $violation->getMessage());
     }
-    $violations = $comment->validate();
-    // Filter out violations for the name path.
+    $violations = $comment->name->validate();
     foreach ($violations as $violation) {
-      if ($violation->getPropertyPath() === 'name') {
-        $form_state->setErrorByName('name', $violation->getMessage());
-      }
+      $form_state->setErrorByName('name', $violation->getMessage());
     }
 
     return $comment;
diff --git a/core/modules/comment/src/Entity/Comment.php b/core/modules/comment/src/Entity/Comment.php
index 2023448..f83f54b 100644
--- a/core/modules/comment/src/Entity/Comment.php
+++ b/core/modules/comment/src/Entity/Comment.php
@@ -54,9 +54,6 @@
  *   },
  *   bundle_entity_type = "comment_type",
  *   field_ui_base_route  = "entity.comment_type.edit_form",
- *   constraints = {
- *     "CommentName" = {}
- *   }
  * )
  */
 class Comment extends ContentEntityBase implements CommentInterface {
@@ -260,7 +257,8 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setDescription(t("The comment author's name."))
       ->setTranslatable(TRUE)
       ->setSetting('max_length', 60)
-      ->setDefaultValue('');
+      ->setDefaultValue('')
+      ->addConstraint('CommentName', array());
 
     $fields['mail'] = BaseFieldDefinition::create('email')
       ->setLabel(t('Email'))
diff --git a/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php b/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php
index 4de6726..d387542 100644
--- a/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php
+++ b/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php
@@ -7,18 +7,17 @@
 
 namespace Drupal\comment\Plugin\Validation\Constraint;
 
-use Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase;
+use Symfony\Component\Validator\Constraint;
 
 /**
  * Supports validating comment author names.
  *
  * @Plugin(
  *   id = "CommentName",
- *   label = @Translation("Comment author name", context = "Validation"),
- *   type = "entity:comment"
+ *   label = @Translation("Comment author name", context = "Validation")
  * )
  */
-class CommentNameConstraint extends CompositeConstraintBase {
+class CommentNameConstraint extends Constraint {
 
   /**
    * Message shown when an anonymous user comments using a registered name.
@@ -41,11 +40,4 @@ class CommentNameConstraint extends CompositeConstraintBase {
    */
   public $messageMatch = 'The specified author name does not match the comment author.';
 
-  /**
-   * {@inheritdoc}
-   */
-  public function coversFields() {
-    return ['name', 'uid'];
-  }
-
 }
diff --git a/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraintValidator.php b/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraintValidator.php
index 915d184..f6397e0 100644
--- a/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraintValidator.php
+++ b/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraintValidator.php
@@ -20,13 +20,6 @@
 class CommentNameConstraintValidator extends ConstraintValidator implements ContainerInjectionInterface {
 
   /**
-   * Validator 2.5 and upwards compatible execution context.
-   *
-   * @var \Symfony\Component\Validator\Context\ExecutionContextInterface
-   */
-  protected $context;
-
-  /**
    * User storage handler.
    *
    * @var \Drupal\user\UserStorageInterface
@@ -53,36 +46,41 @@ public static function create(ContainerInterface $container) {
   /**
    * {@inheritdoc}
    */
-  public function validate($entity, Constraint $constraint) {
-    $author_name = $entity->name->value;
-    $owner_id = (int) $entity->uid->target_id;
+  public function validate($items, Constraint $constraint) {
+    /** @var CommentNameConstraint $constraint */
+    if (!isset($items)) {
+      return;
+    }
+    /** @var CommentInterface $comment */
+    $comment = $items->getEntity();
+
+    if (!isset($comment)) {
+      // Looks like we are validating a field not being part of a comment,
+      // nothing we can do then.
+      return;
+    }
+    $author_name = $items->first()->value;
 
     // Do not allow unauthenticated comment authors to use a name that is
     // taken by a registered user.
-    if (isset($author_name) && $author_name !== '' && $owner_id === 0) {
+    if (isset($author_name) && $author_name !== '' && $comment->getOwnerId() === 0) {
       $users = $this->userStorage->loadByProperties(array('name' => $author_name));
       if (!empty($users)) {
-        $this->context->buildViolation($constraint->messageNameTaken, array('%name' => $author_name))
-          ->atPath('name')
-          ->addViolation();
+        $this->context->addViolation($constraint->messageNameTaken, array('%name' => $author_name));
       }
     }
     // If an author name and owner are given, make sure they match.
-    elseif (isset($author_name) && $author_name !== '' && $owner_id) {
-      $owner = $this->userStorage->load($owner_id);
+    elseif (isset($author_name) && $author_name !== '' && $comment->getOwnerId()) {
+      $owner = $comment->getOwner();
       if ($owner->getUsername() != $author_name) {
-        $this->context->buildViolation($constraint->messageMatch)
-          ->atPath('name')
-          ->addViolation();
+        $this->context->addViolation($constraint->messageMatch);
       }
     }
 
     // Anonymous account might be required - depending on field settings.
-    if ($owner_id === 0 && empty($author_name) &&
-      $this->getAnonymousContactDetailsSetting($entity) === COMMENT_ANONYMOUS_MUST_CONTACT) {
-      $this->context->buildViolation($constraint->messageRequired)
-        ->atPath('name')
-        ->addViolation();
+    if ($comment->getOwnerId() === 0 && empty($author_name) &&
+      $this->getAnonymousContactDetailsSetting($comment) === COMMENT_ANONYMOUS_MUST_CONTACT) {
+      $this->context->addViolation($constraint->messageRequired);
     }
   }
 
diff --git a/core/modules/contextual/src/Element/ContextualLinksPlaceholder.php b/core/modules/contextual/src/Element/ContextualLinksPlaceholder.php
index d10078b..e148a1b 100644
--- a/core/modules/contextual/src/Element/ContextualLinksPlaceholder.php
+++ b/core/modules/contextual/src/Element/ContextualLinksPlaceholder.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Template\Attribute;
 use Drupal\Core\Render\Element\RenderElement;
+use Drupal\Component\Utility\SafeMarkup;
 
 /**
  * Provides a contextual_links_placeholder element.
@@ -47,7 +48,11 @@ public function getInfo() {
    * @see _contextual_links_to_id()
    */
   public static function preRenderPlaceholder(array $element) {
-    $element['#markup'] = '<div' . new Attribute(array('data-contextual-id' => $element['#id'])) . '></div>';
+    // Because the only arguments to this markup will be instance of
+    // \Drupal\Core\Template\AttributeString, which is passed through
+    // \Drupal\Component\Utility\SafeMarkup::checkPlain() before being output
+    // this markup is safe, and is marked as such.
+    $element['#markup'] = SafeMarkup::set('<div' . new Attribute(array('data-contextual-id' => $element['#id'])) . '></div>');
     return $element;
   }
 
diff --git a/core/modules/filter/src/Element/ProcessedText.php b/core/modules/filter/src/Element/ProcessedText.php
index d007b5f..4851a22 100644
--- a/core/modules/filter/src/Element/ProcessedText.php
+++ b/core/modules/filter/src/Element/ProcessedText.php
@@ -8,6 +8,7 @@
 namespace Drupal\filter\Element;
 
 use Drupal\Component\Utility\NestedArray;
+use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Render\BubbleableMetadata;
 use Drupal\Core\Render\Element\RenderElement;
@@ -118,9 +119,11 @@ public static function preRenderText($element) {
       }
     }
 
-    // Filtering done, store in #markup, set the updated bubbleable rendering
-    // metadata, and set the text format's cache tag.
-    $element['#markup'] = $text;
+    // Filtering and sanitizing has been done in
+    // \Drupal\filter\Plugin\FilterInterface. Store its content in #markup,
+    // set the updated bubbleable rendering metadata, and set the text format's
+    // cache tag.
+    $element['#markup'] = SafeMarkup::set($text);
     $metadata->applyTo($element);
     $element['#cache']['tags'] = Cache::mergeTags($element['#cache']['tags'], $format->getCacheTags());
 
diff --git a/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php b/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
index 14fdb0b..a3caa35 100644
--- a/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
+++ b/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
@@ -76,7 +76,7 @@ public function normalize($entity, $format = NULL, array $context = array()) {
           'href' => $this->getEntityUri($entity),
         ),
         'type' => array(
-          'href' => $this->linkManager->getTypeUri($entity->getEntityTypeId(), $entity->bundle(), $context),
+          'href' => $this->linkManager->getTypeUri($entity->getEntityTypeId(), $entity->bundle()),
         ),
       ),
     );
@@ -132,7 +132,7 @@ public function denormalize($data, $class, $format = NULL, array $context = arra
     }
 
     // Create the entity.
-    $typed_data_ids = $this->getTypedDataIds($data['_links']['type'], $context);
+    $typed_data_ids = $this->getTypedDataIds($data['_links']['type']);
     $entity_type = $this->entityManager->getDefinition($typed_data_ids['entity_type']);
     $langcode_key = $entity_type->getKey('langcode');
     $values = array();
@@ -210,14 +210,13 @@ protected function getEntityUri($entity) {
    *
    * @param array $types
    *   The type array(s) (value of the 'type' attribute of the incoming data).
-   * @param array $context
-   *   Context from the normalizer/serializer operation.
    *
    * @return array
    *   The typed data IDs.
    *
+   * @throws \Symfony\Component\Serializer\Exception\UnexpectedValueException
    */
-  protected function getTypedDataIds($types, $context = array()) {
+  protected function getTypedDataIds($types) {
     // The 'type' can potentially contain an array of type objects. By default,
     // Drupal only uses a single type in serializing, but allows for multiple
     // types when deserializing.
@@ -232,7 +231,7 @@ protected function getTypedDataIds($types, $context = array()) {
       $type_uri = $type['href'];
       // Check whether the URI corresponds to a known type on this site. Break
       // once one does.
-      if ($typed_data_ids = $this->linkManager->getTypeInternalIds($type['href'], $context)) {
+      if ($typed_data_ids = $this->linkManager->getTypeInternalIds($type['href'])) {
         break;
       }
     }
diff --git a/core/modules/hal/src/Normalizer/EntityReferenceItemNormalizer.php b/core/modules/hal/src/Normalizer/EntityReferenceItemNormalizer.php
index 5160b68..4b5344a 100644
--- a/core/modules/hal/src/Normalizer/EntityReferenceItemNormalizer.php
+++ b/core/modules/hal/src/Normalizer/EntityReferenceItemNormalizer.php
@@ -85,7 +85,7 @@ public function normalize($field_item, $format = NULL, array $context = array())
     // objects.
     $field_name = $field_item->getParent()->getName();
     $entity = $field_item->getEntity();
-    $field_uri = $this->linkManager->getRelationUri($entity->getEntityTypeId(), $entity->bundle(), $field_name, $context);
+    $field_uri = $this->linkManager->getRelationUri($entity->getEntityTypeId(), $entity->bundle(), $field_name);
     return array(
       '_links' => array(
         $field_uri => array($link),
diff --git a/core/modules/hal/src/Tests/FileNormalizeTest.php b/core/modules/hal/src/Tests/FileNormalizeTest.php
index 64ffd07..2b50381 100644
--- a/core/modules/hal/src/Tests/FileNormalizeTest.php
+++ b/core/modules/hal/src/Tests/FileNormalizeTest.php
@@ -39,7 +39,8 @@ protected function setUp() {
     $this->installEntitySchema('file');
 
     $entity_manager = \Drupal::entityManager();
-    $link_manager = new LinkManager(new TypeLinkManager(new MemoryBackend('default'), \Drupal::moduleHandler(), \Drupal::service('config.factory'), \Drupal::service('request_stack')), new RelationLinkManager(new MemoryBackend('default'), $entity_manager, \Drupal::moduleHandler(), \Drupal::service('config.factory'), \Drupal::service('request_stack')));
+    $url_assembler = \Drupal::service('unrouted_url_assembler');
+    $link_manager = new LinkManager(new TypeLinkManager(new MemoryBackend('default'), $url_assembler), new RelationLinkManager(new MemoryBackend('default'), $entity_manager, $url_assembler));
 
     // Set up the mock serializer.
     $normalizers = array(
diff --git a/core/modules/hal/src/Tests/NormalizerTestBase.php b/core/modules/hal/src/Tests/NormalizerTestBase.php
index aea5b25..43f10b1 100644
--- a/core/modules/hal/src/Tests/NormalizerTestBase.php
+++ b/core/modules/hal/src/Tests/NormalizerTestBase.php
@@ -83,7 +83,6 @@ protected function setUp() {
       $class = get_parent_class($class);
     }
     $this->installConfig(array('field', 'language'));
-    \Drupal::service('router.builder')->rebuild();
 
     // Add German as a language.
     ConfigurableLanguage::create(array(
@@ -135,7 +134,8 @@ protected function setUp() {
     ))->save();
 
     $entity_manager = \Drupal::entityManager();
-    $link_manager = new LinkManager(new TypeLinkManager(new MemoryBackend('default'), \Drupal::moduleHandler(), \Drupal::service('config.factory'), \Drupal::service('request_stack')), new RelationLinkManager(new MemoryBackend('default'), $entity_manager, \Drupal::moduleHandler(), \Drupal::service('config.factory'), \Drupal::service('request_stack')));
+    $url_assembler = \Drupal::service('unrouted_url_assembler');
+    $link_manager = new LinkManager(new TypeLinkManager(new MemoryBackend('default'), $url_assembler), new RelationLinkManager(new MemoryBackend('default'), $entity_manager, $url_assembler));
 
     $chain_resolver = new ChainEntityResolver(array(new UuidResolver($entity_manager), new TargetIdResolver()));
 
diff --git a/core/modules/rest/config/install/rest.settings.yml b/core/modules/rest/config/install/rest.settings.yml
index 0c388ca..0a44346 100644
--- a/core/modules/rest/config/install/rest.settings.yml
+++ b/core/modules/rest/config/install/rest.settings.yml
@@ -44,7 +44,3 @@ resources:
 #
 # The full documentation is located at
 # https://drupal.org/documentation/modules/rest
-
-# Set the domain for REST type and relation links.
-# If left blank, the site's domain will be used
-link_domain: ~
diff --git a/core/modules/rest/config/schema/rest.schema.yml b/core/modules/rest/config/schema/rest.schema.yml
index 8014b31..8421d13 100644
--- a/core/modules/rest/config/schema/rest.schema.yml
+++ b/core/modules/rest/config/schema/rest.schema.yml
@@ -10,9 +10,6 @@ rest.settings:
       sequence:
         type: rest_resource
         label: 'Resource'
-    link_domain:
-      type: string
-      label: 'Domain of the relation'
 
 rest_resource:
   type: mapping
diff --git a/core/modules/rest/rest.api.php b/core/modules/rest/rest.api.php
index fb8993d..2f3f6ee 100644
--- a/core/modules/rest/rest.api.php
+++ b/core/modules/rest/rest.api.php
@@ -29,52 +29,5 @@ function hook_rest_resource_alter(&$definitions) {
 }
 
 /**
- * Alter the REST type URI.
- *
- * Modules may wish to alter the type URI generated for a resource based on the
- * context of the serializer/normalizer operation.
- *
- * @param string $uri
- *   The URI to alter.
- * @param array $context
- *   The context from the serializer/normalizer operation.
- *
- * @see \Symfony\Component\Serializer\SerializerInterface::serialize()
- * @see \Symfony\Component\Serializer\SerializerInterface::deserialize()
- * @see \Symfony\Component\Serializer\NormalizerInterface::normalize()
- * @see \Symfony\Component\Serializer\DenormalizerInterface::denormalize()
- */
-function hook_rest_type_uri_alter(&$uri, $context = array()) {
-  if ($context['mymodule'] == TRUE) {
-    $base = \Drupal::config('rest.settings')->get('link_domain');
-    $uri = str_replace($base, 'http://mymodule.domain', $uri);
-  }
-}
-
-
-/**
- * Alter the REST relation URI.
- *
- * Modules may wish to alter the relation URI generated for a resource based on
- * the context of the serializer/normalizer operation.
- *
- * @param string $uri
- *   The URI to alter.
- * @param array $context
- *   The context from the serializer/normalizer operation.
- *
- * @see \Symfony\Component\Serializer\SerializerInterface::serialize()
- * @see \Symfony\Component\Serializer\SerializerInterface::deserialize()
- * @see \Symfony\Component\Serializer\NormalizerInterface::normalize()
- * @see \Symfony\Component\Serializer\DenormalizerInterface::denormalize()
- */
-function hook_rest_relation_uri_alter(&$uri, $context = array()) {
-  if ($context['mymodule'] == TRUE) {
-    $base = \Drupal::config('rest.settings')->get('link_domain');
-    $uri = str_replace($base, 'http://mymodule.domain', $uri);
-  }
-}
-
-/**
  * @} End of "addtogroup hooks".
  */
diff --git a/core/modules/rest/rest.services.yml b/core/modules/rest/rest.services.yml
index 04f5f1d..bfba7bb 100644
--- a/core/modules/rest/rest.services.yml
+++ b/core/modules/rest/rest.services.yml
@@ -19,10 +19,10 @@ services:
     arguments: ['@rest.link_manager.type', '@rest.link_manager.relation']
   rest.link_manager.type:
     class: Drupal\rest\LinkManager\TypeLinkManager
-    arguments: ['@cache.default', '@module_handler', '@config.factory', '@request_stack']
+    arguments: ['@cache.default', '@unrouted_url_assembler']
   rest.link_manager.relation:
     class: Drupal\rest\LinkManager\RelationLinkManager
-    arguments: ['@cache.default', '@entity.manager', '@module_handler', '@config.factory', '@request_stack']
+    arguments: ['@cache.default', '@entity.manager', '@unrouted_url_assembler']
   rest.resource_routes:
     class: Drupal\rest\Routing\ResourceRoutes
     arguments: ['@plugin.manager.rest', '@config.factory', '@logger.channel.rest']
diff --git a/core/modules/rest/src/LinkManager/ConfigurableLinkManagerInterface.php b/core/modules/rest/src/LinkManager/ConfigurableLinkManagerInterface.php
deleted file mode 100644
index 0505811..0000000
--- a/core/modules/rest/src/LinkManager/ConfigurableLinkManagerInterface.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\rest\LinkManager\ConfigurableLinkManagerInterface.
- */
-
-namespace Drupal\rest\LinkManager;
-
-/**
- * Defines an interface for a link manager with a configurable domain.
- */
-interface ConfigurableLinkManagerInterface {
-
-  /**
-   * Sets the link domain used in constructing link URIs.
-   *
-   * @param string $domain
-   *   The link domain to use for constructing link URIs.
-   *
-   * @return $this
-   */
-  public function setLinkDomain($domain);
-
-}
diff --git a/core/modules/rest/src/LinkManager/LinkManager.php b/core/modules/rest/src/LinkManager/LinkManager.php
index 3d70a05..3e61ca6 100644
--- a/core/modules/rest/src/LinkManager/LinkManager.php
+++ b/core/modules/rest/src/LinkManager/LinkManager.php
@@ -38,22 +38,22 @@ public function __construct(TypeLinkManagerInterface $type_link_manager, Relatio
   /**
    * Implements \Drupal\rest\LinkManager\TypeLinkManagerInterface::getTypeUri().
    */
-  public function getTypeUri($entity_type, $bundle, $context = array()) {
-    return $this->typeLinkManager->getTypeUri($entity_type, $bundle, $context);
+  public function getTypeUri($entity_type, $bundle) {
+    return $this->typeLinkManager->getTypeUri($entity_type, $bundle);
   }
 
   /**
    * Implements \Drupal\rest\LinkManager\TypeLinkManagerInterface::getTypeInternalIds().
    */
-  public function getTypeInternalIds($type_uri, $context = array()) {
-    return $this->typeLinkManager->getTypeInternalIds($type_uri, $context);
+  public function getTypeInternalIds($type_uri) {
+    return $this->typeLinkManager->getTypeInternalIds($type_uri);
   }
 
   /**
    * Implements \Drupal\rest\LinkManager\RelationLinkManagerInterface::getRelationUri().
    */
-  public function getRelationUri($entity_type, $bundle, $field_name, $context = array()) {
-    return $this->relationLinkManager->getRelationUri($entity_type, $bundle, $field_name, $context);
+  public function getRelationUri($entity_type, $bundle, $field_name) {
+    return $this->relationLinkManager->getRelationUri($entity_type, $bundle, $field_name);
   }
 
   /**
@@ -63,13 +63,4 @@ public function getRelationInternalIds($relation_uri) {
     return $this->relationLinkManager->getRelationInternalIds($relation_uri);
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function setLinkDomain($domain) {
-    $this->relationLinkManager->setLinkDomain($domain);
-    $this->typeLinkManager->setLinkDomain($domain);
-    return $this;
-  }
-
 }
diff --git a/core/modules/rest/src/LinkManager/LinkManagerBase.php b/core/modules/rest/src/LinkManager/LinkManagerBase.php
deleted file mode 100644
index f93f6fd..0000000
--- a/core/modules/rest/src/LinkManager/LinkManagerBase.php
+++ /dev/null
@@ -1,64 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\rest\LinkManager\LinkManagerBase.
- */
-
-namespace Drupal\rest\LinkManager;
-use Drupal\Core\Url;
-
-/**
- * Defines an abstract base-class for REST link manager objects.
- */
-abstract class LinkManagerBase {
-
-  /**
-   * Link domain used for type links URIs.
-   *
-   * @var string
-   */
-  protected $linkDomain;
-
-  /**
-   * Config factory service.
-   *
-   * @var \Drupal\Core\Config\ConfigFactoryInterface
-   */
-  protected $configFactory;
-
-  /**
-   * The request stack.
-   *
-   * @var \Symfony\Component\HttpFoundation\RequestStack
-   */
-  protected $requestStack;
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setLinkDomain($domain) {
-    $this->linkDomain = rtrim($domain, '/');
-    return $this;
-  }
-
-  /**
-   * Gets the link domain.
-   *
-   * @return string
-   *   The link domain.
-   */
-  protected function getLinkDomain() {
-    if (empty($this->linkDomain)) {
-      if ($domain = $this->configFactory->get('rest.settings')->get('link_domain')) {
-        $this->linkDomain = rtrim($domain, '/');
-      }
-      else {
-        $request = $this->requestStack->getCurrentRequest();
-        $this->linkDomain = $request->getSchemeAndHttpHost() . $request->getBasePath();
-      }
-    }
-    return $this->linkDomain;
-  }
-
-}
diff --git a/core/modules/rest/src/LinkManager/RelationLinkManager.php b/core/modules/rest/src/LinkManager/RelationLinkManager.php
index 9cdd5c4..38bf4cf 100644
--- a/core/modules/rest/src/LinkManager/RelationLinkManager.php
+++ b/core/modules/rest/src/LinkManager/RelationLinkManager.php
@@ -9,13 +9,11 @@
 
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheBackendInterface;
-use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Entity\ContentEntityTypeInterface;
 use Drupal\Core\Entity\EntityManagerInterface;
-use Drupal\Core\Extension\ModuleHandlerInterface;
-use Symfony\Component\HttpFoundation\RequestStack;
+use Drupal\Core\Utility\UnroutedUrlAssemblerInterface;
 
-class RelationLinkManager extends LinkManagerBase implements RelationLinkManagerInterface {
+class RelationLinkManager implements RelationLinkManagerInterface {
 
   /**
    * @var \Drupal\Core\Cache\CacheBackendInterface;
@@ -30,11 +28,11 @@ class RelationLinkManager extends LinkManagerBase implements RelationLinkManager
   protected $entityManager;
 
   /**
-   * Module handler service.
+   * The unrouted URL assembler.
    *
-   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   * @var \Drupal\Core\Utility\UnroutedUrlAssemblerInterface
    */
-  protected $moduleHandler;
+  protected $urlAssembler;
 
   /**
    * Constructor.
@@ -43,35 +41,27 @@ class RelationLinkManager extends LinkManagerBase implements RelationLinkManager
    *   The cache of relation URIs and their associated Typed Data IDs.
    * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
    *   The entity manager.
-   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
-   *   The module handler service.
-   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
-   *   The config factory service.
-   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
-   *   The request stack.
+   * @param \Drupal\Core\Utility\UnroutedUrlAssemblerInterface $url_assembler
+   *   The unrouted URL assembler.
    */
-  public function __construct(CacheBackendInterface $cache, EntityManagerInterface $entity_manager, ModuleHandlerInterface $module_handler, ConfigFactoryInterface $config_factory, RequestStack $request_stack) {
+  public function __construct(CacheBackendInterface $cache, EntityManagerInterface $entity_manager, UnroutedUrlAssemblerInterface $url_assembler) {
     $this->cache = $cache;
     $this->entityManager = $entity_manager;
-    $this->configFactory = $config_factory;
-    $this->moduleHandler = $module_handler;
-    $this->requestStack = $request_stack;
+    $this->urlAssembler = $url_assembler;
   }
 
   /**
    * {@inheritdoc}
    */
-  public function getRelationUri($entity_type, $bundle, $field_name, $context = array()) {
-    $uri = $this->getLinkDomain() . "/rest/relation/$entity_type/$bundle/$field_name";
-    $this->moduleHandler->alter('rest_relation_uri', $uri, $context);
-    return $uri;
+  public function getRelationUri($entity_type, $bundle, $field_name) {
+    return $this->urlAssembler->assemble("base:rest/relation/$entity_type/$bundle/$field_name", array('absolute' => TRUE));
   }
 
   /**
    * {@inheritdoc}
    */
-  public function getRelationInternalIds($relation_uri, $context = array()) {
-    $relations = $this->getRelations($context);
+  public function getRelationInternalIds($relation_uri) {
+    $relations = $this->getRelations();
     if (isset($relations[$relation_uri])) {
       return $relations[$relation_uri];
     }
@@ -87,18 +77,15 @@ public function getRelationInternalIds($relation_uri, $context = array()) {
    * even primitives, are given a relation URI. It is up to the caller to
    * determine which URIs to use.
    *
-   * @param array $context
-   *   Context from the normalizer/serializer operation.
-   *
    * @return array
    *   An array of typed data ids (entity_type, bundle, and field name) keyed
    *   by corresponding relation URI.
    */
-  protected function getRelations($context = array()) {
+  protected function getRelations() {
     $cid = 'rest:links:relations';
     $cache = $this->cache->get($cid);
     if (!$cache) {
-      $this->writeCache($context);
+      $this->writeCache();
       $cache = $this->cache->get($cid);
     }
     return $cache->data;
@@ -106,18 +93,15 @@ protected function getRelations($context = array()) {
 
   /**
    * Writes the cache of relation links.
-   *
-   * @param array $context
-   *   Context from the normalizer/serializer operation.
    */
-  protected function writeCache($context = array()) {
+  protected function writeCache() {
     $data = array();
 
     foreach ($this->entityManager->getDefinitions() as $entity_type) {
       if ($entity_type instanceof ContentEntityTypeInterface) {
         foreach ($this->entityManager->getBundleInfo($entity_type->id()) as $bundle => $bundle_info) {
           foreach ($this->entityManager->getFieldDefinitions($entity_type->id(), $bundle) as $field_definition) {
-            $relation_uri = $this->getRelationUri($entity_type->id(), $bundle, $field_definition->getName(), $context);
+            $relation_uri = $this->getRelationUri($entity_type->id(), $bundle, $field_definition->getName());
             $data[$relation_uri] = array(
               'entity_type' => $entity_type,
               'bundle' => $bundle,
diff --git a/core/modules/rest/src/LinkManager/RelationLinkManagerInterface.php b/core/modules/rest/src/LinkManager/RelationLinkManagerInterface.php
index f99e43e..2dc175c 100644
--- a/core/modules/rest/src/LinkManager/RelationLinkManagerInterface.php
+++ b/core/modules/rest/src/LinkManager/RelationLinkManagerInterface.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\rest\LinkManager;
 
-interface RelationLinkManagerInterface extends ConfigurableLinkManagerInterface {
+interface RelationLinkManagerInterface {
 
   /**
    * Gets the URI that corresponds to a field.
@@ -18,13 +18,11 @@
    *   The bundle name.
    * @param string $field_name
    *   The field name.
-   * @param array $context
-   *   (optional) Optional serializer/normalizer context.
    *
    * @return string
    *   The corresponding URI for the field.
    */
-  public function getRelationUri($entity_type, $bundle, $field_name, $context = array());
+  public function getRelationUri($entity_type, $bundle, $field_name);
 
   /**
    * Translates a REST URI into internal IDs.
diff --git a/core/modules/rest/src/LinkManager/TypeLinkManager.php b/core/modules/rest/src/LinkManager/TypeLinkManager.php
index 3c9f665..4160b2b 100644
--- a/core/modules/rest/src/LinkManager/TypeLinkManager.php
+++ b/core/modules/rest/src/LinkManager/TypeLinkManager.php
@@ -9,11 +9,9 @@
 
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheBackendInterface;
-use Drupal\Core\Config\ConfigFactoryInterface;
-use Drupal\Core\Extension\ModuleHandlerInterface;
-use Symfony\Component\HttpFoundation\RequestStack;
+use Drupal\Core\Utility\UnroutedUrlAssemblerInterface;
 
-class TypeLinkManager extends LinkManagerBase implements TypeLinkManagerInterface {
+class TypeLinkManager implements TypeLinkManagerInterface {
 
   /**
    * Injected cache backend.
@@ -23,29 +21,23 @@ class TypeLinkManager extends LinkManagerBase implements TypeLinkManagerInterfac
   protected $cache;
 
   /**
-   * Module handler service.
+   * The unrouted URL assembler.
    *
-   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   * @var \Drupal\Core\Utility\UnroutedUrlAssemblerInterface
    */
-  protected $moduleHandler;
+  protected $urlAssembler;
 
   /**
    * Constructor.
    *
    * @param \Drupal\Core\Cache\CacheBackendInterface $cache
    *   The injected cache backend for caching type URIs.
-   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
-   *   The module handler service.
-   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
-   *   The config factory service.
-   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
-   *   The request stack.
+   * @param \Drupal\Core\Utility\UnroutedUrlAssemblerInterface $url_assembler
+   *   The unrouted URL assembler.
    */
-  public function __construct(CacheBackendInterface $cache, ModuleHandlerInterface $module_handler, ConfigFactoryInterface $config_factory, RequestStack $request_stack) {
+  public function __construct(CacheBackendInterface $cache, UnroutedUrlAssemblerInterface $url_assembler) {
     $this->cache = $cache;
-    $this->configFactory = $config_factory;
-    $this->moduleHandler = $module_handler;
-    $this->requestStack = $request_stack;
+    $this->urlAssembler = $url_assembler;
   }
 
   /**
@@ -55,23 +47,20 @@ public function __construct(CacheBackendInterface $cache, ModuleHandlerInterface
    *   The bundle's entity type.
    * @param string $bundle
    *   The name of the bundle.
-   * @param array $context
-   *   Context of normalizer/serializer.
    *
-   * @return string
+   * @return array
    *   The URI that identifies this bundle.
    */
-  public function getTypeUri($entity_type, $bundle, $context = array()) {
-    $uri = $this->getLinkDomain() . "/rest/type/$entity_type/$bundle";
-    $this->moduleHandler->alter('rest_type_uri', $uri, $context);
-    return $uri;
+  public function getTypeUri($entity_type, $bundle) {
+    // @todo Make the base path configurable.
+    return $this->urlAssembler->assemble("base:rest/type/$entity_type/$bundle", array('absolute' => TRUE));
   }
 
   /**
    * Implements \Drupal\rest\LinkManager\TypeLinkManagerInterface::getTypeInternalIds().
    */
-  public function getTypeInternalIds($type_uri, $context = array()) {
-    $types = $this->getTypes($context);
+  public function getTypeInternalIds($type_uri) {
+    $types = $this->getTypes();
     if (isset($types[$type_uri])) {
       return $types[$type_uri];
     }
@@ -81,18 +70,15 @@ public function getTypeInternalIds($type_uri, $context = array()) {
   /**
    * Get the array of type links.
    *
-   * @param array $context
-   *   Context from the normalizer/serializer operation.
-   *
    * @return array
    *   An array of typed data ids (entity_type and bundle) keyed by
    *   corresponding type URI.
    */
-  protected function getTypes($context = array()) {
+  protected function getTypes() {
     $cid = 'rest:links:types';
     $cache = $this->cache->get($cid);
     if (!$cache) {
-      $this->writeCache($context);
+      $this->writeCache();
       $cache = $this->cache->get($cid);
     }
     return $cache->data;
@@ -100,11 +86,8 @@ protected function getTypes($context = array()) {
 
   /**
    * Writes the cache of type links.
-   *
-   * @param array $context
-   *   Context from the normalizer/serializer operation.
    */
-  protected function writeCache($context = array()) {
+  protected function writeCache() {
     $data = array();
 
     // Type URIs correspond to bundles. Iterate through the bundles to get the
@@ -118,7 +101,7 @@ protected function writeCache($context = array()) {
       }
       foreach ($bundles as $bundle => $bundle_info) {
         // Get a type URI for the bundle.
-        $bundle_uri = $this->getTypeUri($entity_type_id, $bundle, $context);
+        $bundle_uri = $this->getTypeUri($entity_type_id, $bundle);
         $data[$bundle_uri] = array(
           'entity_type' => $entity_type_id,
           'bundle' => $bundle,
@@ -129,5 +112,4 @@ protected function writeCache($context = array()) {
     // and only clear it when entity_info is cleared.
     $this->cache->set('rest:links:types', $data, Cache::PERMANENT, array('entity_types'));
   }
-
 }
diff --git a/core/modules/rest/src/LinkManager/TypeLinkManagerInterface.php b/core/modules/rest/src/LinkManager/TypeLinkManagerInterface.php
index 3459d06..9c2d942 100644
--- a/core/modules/rest/src/LinkManager/TypeLinkManagerInterface.php
+++ b/core/modules/rest/src/LinkManager/TypeLinkManagerInterface.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\rest\LinkManager;
 
-interface TypeLinkManagerInterface extends ConfigurableLinkManagerInterface {
+interface TypeLinkManagerInterface {
 
   /**
    * Gets the URI that corresponds to a bundle.
@@ -20,25 +20,21 @@
    *   The bundle's entity type.
    * @param $bundle
    *   The bundle name.
-   * @param array $context
-   *   (optional) Optional serializer/normalizer context.
    *
    * @return string
    *   The corresponding URI for the bundle.
    */
-  public function getTypeUri($entity_type, $bundle, $context = array());
+  public function getTypeUri($entity_type, $bundle);
 
   /**
    * Get a bundle's Typed Data IDs based on a URI.
    *
    * @param string $type_uri
    *   The type URI.
-   * @param array $context
-   *   Context from the normalizer/serializer operation.
    *
    * @return array | boolean
    *   If the URI matches a bundle, returns an array containing entity_type and
    *   bundle. Otherwise, returns false.
    */
-  public function getTypeInternalIds($type_uri, $context = array());
+  public function getTypeInternalIds($type_uri);
 }
diff --git a/core/modules/rest/src/Plugin/views/display/RestExport.php b/core/modules/rest/src/Plugin/views/display/RestExport.php
index 8af1a75..0cd43e9 100644
--- a/core/modules/rest/src/Plugin/views/display/RestExport.php
+++ b/core/modules/rest/src/Plugin/views/display/RestExport.php
@@ -278,7 +278,7 @@ public function execute() {
     $header = [];
     $header['Content-type'] = $this->getMimeType();
 
-    $response = new CacheableResponse($this->renderer->renderRoot($output), 200);
+    $response = new CacheableResponse($output['#markup'], 200);
     $cache_metadata = CacheableMetadata::createFromRenderArray($output);
 
     $response->addCacheableDependency($cache_metadata);
diff --git a/core/modules/rest/src/Plugin/views/style/Serializer.php b/core/modules/rest/src/Plugin/views/style/Serializer.php
index 09e94e6..6078c9f 100644
--- a/core/modules/rest/src/Plugin/views/style/Serializer.php
+++ b/core/modules/rest/src/Plugin/views/style/Serializer.php
@@ -7,7 +7,9 @@
 
 namespace Drupal\rest\Plugin\views\style;
 
+use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\rest\Plugin\views\row\DataFieldRow;
 use Drupal\views\ViewExecutable;
 use Drupal\views\Plugin\views\display\DisplayPluginBase;
 use Drupal\views\Plugin\views\style\StylePluginBase;
diff --git a/core/modules/rest/src/Tests/RestLinkManagerTest.php b/core/modules/rest/src/Tests/RestLinkManagerTest.php
deleted file mode 100644
index 4adee7c..0000000
--- a/core/modules/rest/src/Tests/RestLinkManagerTest.php
+++ /dev/null
@@ -1,90 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\rest\Tests\RestLinkManagerTest.
- */
-
-namespace Drupal\rest\Tests;
-use Drupal\Core\Url;
-use Drupal\simpletest\KernelTestBase;
-
-/**
- * Tests that REST type and relation link managers work as expected
- * @group rest
- */
-class RestLinkManagerTest extends KernelTestBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  public static $modules = ['rest', 'rest_test', 'system'];
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-    $this->installSchema('system', ['router']);
-    \Drupal::service('router.builder')->rebuild();
-  }
-
-  /**
-   * Tests that type hooks work as expected.
-   */
-  public function testRestLinkManagers() {
-    \Drupal::moduleHandler()->invoke('rest', 'install');
-    /* @var \Drupal\rest\LinkManager\TypeLinkManagerInterface $type_manager */
-    $type_manager = \Drupal::service('rest.link_manager.type');
-    $base = Url::fromRoute('<front>', [], ['absolute' => TRUE])->toString();
-    $link = $type_manager->getTypeUri('node', 'page');
-    $this->assertEqual($link, $base . 'rest/type/node/page');
-    // Now with optional context.
-    $link = $type_manager->getTypeUri('node', 'page', ['rest_test' => TRUE]);
-    $this->assertEqual($link, 'rest_test_type');
-
-    /* @var \Drupal\rest\LinkManager\RelationLinkManagerInterface $relation_manager */
-    $relation_manager = \Drupal::service('rest.link_manager.relation');
-    $link = $relation_manager->getRelationUri('node', 'page', 'field_ref');
-    $this->assertEqual($link, $base . 'rest/relation/node/page/field_ref');
-    // Now with optional context.
-    $link = $relation_manager->getRelationUri('node', 'page', 'foobar', ['rest_test' => TRUE]);
-    $this->assertEqual($link, 'rest_test_relation');
-  }
-
-  /**
-   * Tests that type hooks work as expected even without install hook.
-   */
-  public function testRestLinkManagersNoInstallHook() {
-    /* @var \Drupal\rest\LinkManager\TypeLinkManagerInterface $type_manager */
-    $type_manager = \Drupal::service('rest.link_manager.type');
-    $base = Url::fromRoute('<front>', [], ['absolute' => TRUE])->toString();
-    $link = $type_manager->getTypeUri('node', 'page');
-    $this->assertEqual($link, $base . 'rest/type/node/page');
-    // Now with optional context.
-    $link = $type_manager->getTypeUri('node', 'page', ['rest_test' => TRUE]);
-    $this->assertEqual($link, 'rest_test_type');
-
-    /* @var \Drupal\rest\LinkManager\RelationLinkManagerInterface $relation_manager */
-    $relation_manager = \Drupal::service('rest.link_manager.relation');
-    $link = $relation_manager->getRelationUri('node', 'page', 'field_ref');
-    $this->assertEqual($link, $base . 'rest/relation/node/page/field_ref');
-    // Now with optional context.
-    $link = $relation_manager->getRelationUri('node', 'page', 'foobar', ['rest_test' => TRUE]);
-    $this->assertEqual($link, 'rest_test_relation');
-  }
-
-  /**
-   * Tests \Drupal\rest\LinkManager\LinkManager::setLinkDomain().
-   */
-  public function testRestLinkManagersSetLinkDomain() {
-    /* @var \Drupal\rest\LinkManager\LinkManager $link_manager */
-    $link_manager = \Drupal::service('rest.link_manager');
-    $link_manager->setLinkDomain('http://example.com/');
-    $link = $link_manager->getTypeUri('node', 'page');
-    $this->assertEqual($link, 'http://example.com/rest/type/node/page');
-    $link = $link_manager->getRelationUri('node', 'page', 'field_ref');
-    $this->assertEqual($link, 'http://example.com/rest/relation/node/page/field_ref');
-  }
-
-}
diff --git a/core/modules/rest/src/Tests/Views/StyleSerializerTest.php b/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
index 137e8f0..e16556c 100644
--- a/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
+++ b/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
@@ -335,6 +335,16 @@ public function testFieldapiField() {
     $result = $this->drupalGetJSON('test/serialize/node-field');
     $this->assertEqual($result[0]['nid'], $node->id());
     $this->assertEqual($result[0]['body'], $node->body->processed);
-  }
 
+    // Make sure that serialized fields are not exposed to XSS.
+    $node = $this->drupalCreateNode();
+    $node->body = array(
+      'value' => '<script type="text/javascript">alert("node-body");</script>' . $this->randomMachineName(32),
+      'format' => filter_default_format(),
+    );
+    $node->save();
+    $result = $this->drupalGetJSON('test/serialize/node-field');
+    $this->assertEqual($result[1]['nid'], $node->id());
+    $this->assertTrue(strpos($this->getRawContent(), "<script") === FALSE, "The Raw page contents are escaped.");
+  }
 }
diff --git a/core/modules/rest/tests/modules/rest_test/rest_test.info.yml b/core/modules/rest/tests/modules/rest_test/rest_test.info.yml
deleted file mode 100644
index b5f4966..0000000
--- a/core/modules/rest/tests/modules/rest_test/rest_test.info.yml
+++ /dev/null
@@ -1,8 +0,0 @@
-name: 'REST test'
-type: module
-description: 'Provides test hooks for REST module.'
-package: Testing
-version: VERSION
-core: 8.x
-dependencies:
-  - rest
diff --git a/core/modules/rest/tests/modules/rest_test/rest_test.module b/core/modules/rest/tests/modules/rest_test/rest_test.module
deleted file mode 100644
index 272603d..0000000
--- a/core/modules/rest/tests/modules/rest_test/rest_test.module
+++ /dev/null
@@ -1,24 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains hook implementations for testing REST module.
- */
-
-/**
- * Implements hook_rest_type_uri_alter().
- */
-function rest_test_rest_type_uri_alter(&$uri, $context = array()) {
-  if (!empty($context['rest_test'])) {
-    $uri = 'rest_test_type';
-  }
-}
-
-/**
- * Implements hook_rest_relation_uri_alter().
- */
-function rest_test_rest_relation_uri_alter(&$uri, $context = array()) {
-  if (!empty($context['rest_test'])) {
-    $uri = 'rest_test_relation';
-  }
-}
diff --git a/core/modules/serialization/src/Tests/EntityResolverTest.php b/core/modules/serialization/src/Tests/EntityResolverTest.php
index 7d174c3..7d7c00d 100644
--- a/core/modules/serialization/src/Tests/EntityResolverTest.php
+++ b/core/modules/serialization/src/Tests/EntityResolverTest.php
@@ -32,6 +32,7 @@ class EntityResolverTest extends NormalizerTestBase {
   protected function setUp() {
     parent::setUp();
 
+    $this->installSchema('system', 'router');
     \Drupal::service('router.builder')->rebuild();
 
     // Create the test field storage.
diff --git a/core/modules/serialization/src/Tests/NormalizerTestBase.php b/core/modules/serialization/src/Tests/NormalizerTestBase.php
index 8ac4485..3078f84 100644
--- a/core/modules/serialization/src/Tests/NormalizerTestBase.php
+++ b/core/modules/serialization/src/Tests/NormalizerTestBase.php
@@ -23,10 +23,8 @@ protected function setUp() {
 
     $this->installEntitySchema('entity_test_mulrev');
     $this->installEntitySchema('user');
-    $this->installSchema('system', array('url_alias', 'router'));
+    $this->installSchema('system', array('url_alias'));
     $this->installConfig(array('field'));
-    \Drupal::service('router.builder')->rebuild();
-    \Drupal::moduleHandler()->invoke('rest', 'install');
 
     // Auto-create a field for testing.
     entity_create('field_storage_config', array(
diff --git a/core/modules/system/src/Tests/Entity/EntityValidationTest.php b/core/modules/system/src/Tests/Entity/EntityValidationTest.php
index d4358fc..07823fb 100644
--- a/core/modules/system/src/Tests/Entity/EntityValidationTest.php
+++ b/core/modules/system/src/Tests/Entity/EntityValidationTest.php
@@ -7,8 +7,6 @@
 
 namespace Drupal\system\Tests\Entity;
 
-use Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase;
-
 /**
  * Tests the Entity Validation API.
  *
@@ -63,6 +61,7 @@ protected function setUp() {
   protected function createTestEntity($entity_type) {
     $this->entityName = $this->randomMachineName();
     $this->entityUser = $this->createUser();
+    $this->entityFieldText = $this->randomMachineName();
 
     // Pass in the value of the name field when creating. With the user
     // field we test setting a field after creation.
@@ -71,10 +70,7 @@ protected function createTestEntity($entity_type) {
     $entity->name->value = $this->entityName;
 
     // Set a value for the test field.
-    if ($entity->hasField('field_test_text')) {
-      $this->entityFieldText = $this->randomMachineName();
-      $entity->field_test_text->value = $this->entityFieldText;
-    }
+    $entity->field_test_text->value = $this->entityFieldText;
 
     return $entity;
   }
@@ -172,27 +168,4 @@ protected function checkValidation($entity_type) {
     $this->assertEqual($violation->getInvalidValue(), $test_entity->field_test_text->format, 'Violation contains invalid value.');
   }
 
-  /**
-   * Tests composite constraints.
-   */
-  public function testCompositeConstraintValidation() {
-    $entity = $this->createTestEntity('entity_test_composite_constraint');
-    $violations = $entity->validate();
-    $this->assertEqual($violations->count(), 0);
-
-    // Trigger violation condition.
-    $entity->name->value = 'test';
-    $entity->type->value = 'test2';
-    $violations = $entity->validate();
-    $this->assertEqual($violations->count(), 1);
-
-    // Make sure we can determine this is composite constraint.
-    $constraint = $violations[0]->getConstraint();
-    $this->assertTrue($constraint instanceof CompositeConstraintBase, 'Constraint is composite constraint.');
-    $this->assertEqual('type', $violations[0]->getPropertyPath());
-
-    /** @var CompositeConstraintBase $constraint */
-    $this->assertEqual($constraint->coversFields(), ['name', 'type'], 'Information about covered fields can be retrieved.');
-  }
-
 }
diff --git a/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestCompositeConstraint.php b/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestCompositeConstraint.php
deleted file mode 100644
index c387b93..0000000
--- a/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestCompositeConstraint.php
+++ /dev/null
@@ -1,31 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\entity_test\Entity\EntityTestCompositeConstraint.
- */
-
-namespace Drupal\entity_test\Entity;
-
-/**
- * Defines a test class for testing composite constraints.
- *
- * @ContentEntityType(
- *   id = "entity_test_composite_constraint",
- *   label = @Translation("Test entity constraints with composite constraint"),
- *   entity_keys = {
- *     "id" = "id",
- *     "uuid" = "uuid",
- *     "bundle" = "type",
- *     "label" = "name"
- *   },
- *   base_table = "entity_test_composite_constraint",
- *   persistent_cache = FALSE,
- *   constraints = {
- *     "EntityTestComposite" = {},
- *   }
- * )
- */
-class EntityTestCompositeConstraint extends EntityTest {
-
-}
diff --git a/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraint.php b/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraint.php
deleted file mode 100644
index c3b6ce8..0000000
--- a/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraint.php
+++ /dev/null
@@ -1,32 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\entity_test\Plugin\Validation\Constraint\EntityTestCompositeConstraint.
- */
-
-namespace Drupal\entity_test\Plugin\Validation\Constraint;
-
-use Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase;
-
-/**
- * Constraint with multiple fields.
- *
- * @Plugin(
- *   id = "EntityTestComposite",
- *   label = @Translation("Constraint with multiple fields."),
- *   type = "entity"
- * )
- */
-class EntityTestCompositeConstraint extends CompositeConstraintBase {
-
-  public $message = 'Multiple fields are validated';
-
-  /**
-   * {@inheritdoc}
-   */
-  public function coversFields() {
-    return ['name', 'type'];
-  }
-
-}
diff --git a/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraintValidator.php b/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraintValidator.php
deleted file mode 100644
index 54fb969..0000000
--- a/core/modules/system/tests/modules/entity_test/src/Plugin/Validation/Constraint/EntityTestCompositeConstraintValidator.php
+++ /dev/null
@@ -1,38 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\entity_test\Plugin\Validation\Constraint\EntityTestCompositeConstraintValidator.
- */
-
-namespace Drupal\entity_test\Plugin\Validation\Constraint;
-
-use Symfony\Component\Validator\Constraint;
-use Symfony\Component\Validator\ConstraintValidator;
-
-/**
- * Constraint validator for the EntityTestComposite constraint.
- */
-class EntityTestCompositeConstraintValidator extends ConstraintValidator {
-
-  /**
-   * Validator 2.5 and upwards compatible execution context.
-   *
-   * @var \Symfony\Component\Validator\Context\ExecutionContextInterface
-   */
-  protected $context;
-
-  /**
-   * {@inheritdoc}
-   */
-  public function validate($entity, Constraint $constraint) {
-
-    if ($entity->name->value === 'test' && $entity->type->value === 'test2') {
-      $this->context->buildViolation($constraint->message)
-        ->atPath('type')
-        ->addViolation();
-    }
-
-  }
-
-}
diff --git a/core/modules/toolbar/src/Element/ToolbarItem.php b/core/modules/toolbar/src/Element/ToolbarItem.php
index b772193..929dac4 100644
--- a/core/modules/toolbar/src/Element/ToolbarItem.php
+++ b/core/modules/toolbar/src/Element/ToolbarItem.php
@@ -61,7 +61,7 @@ public static function preRenderToolbarItem($element) {
       // Provide attributes necessary for trays.
       $attributes += array(
         'data-toolbar-tray' => $id . '-tray',
-        'aria-owns' => $id . '-tray',
+        'aria-owns' => $id,
         'role' => 'button',
         'aria-pressed' => 'false',
       );
@@ -75,6 +75,7 @@ public static function preRenderToolbarItem($element) {
       $attributes = array(
         'id' => $id . '-tray',
         'data-toolbar-tray' => $id . '-tray',
+        'aria-owned-by' => $id,
       );
       // Merge in module-provided attributes.
       if (!isset($element['tray']['#wrapper_attributes'])) {
diff --git a/core/modules/views/src/Tests/Handler/AreaTest.php b/core/modules/views/src/Tests/Handler/AreaTest.php
index 03b8b57..8bcb173 100644
--- a/core/modules/views/src/Tests/Handler/AreaTest.php
+++ b/core/modules/views/src/Tests/Handler/AreaTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\views\Tests\Handler;
 
+use Drupal\Component\Utility\SafeMarkup;
 use Drupal\views\Views;
 
 /**
@@ -107,9 +108,9 @@ public function testRenderArea() {
     // Check whether the strings exists in the output.
     $output = $view->preview();
     $output = drupal_render($output);
-    $this->assertTrue(strpos($output, $header_string) !== FALSE);
-    $this->assertTrue(strpos($output, $footer_string) !== FALSE);
-    $this->assertTrue(strpos($output, $empty_string) !== FALSE);
+    $this->assertTrue(strpos($output, SafeMarkup::checkPlain($header_string)) !== FALSE);
+    $this->assertTrue(strpos($output, SafeMarkup::checkPlain($footer_string)) !== FALSE);
+    $this->assertTrue(strpos($output, SafeMarkup::checkPlain($empty_string)) !== FALSE);
   }
 
   /**
diff --git a/core/modules/views/views.module b/core/modules/views/views.module
index 41ff298..bae7e06 100644
--- a/core/modules/views/views.module
+++ b/core/modules/views/views.module
@@ -679,7 +679,7 @@ function views_pre_render_views_form_views_form($element) {
   }
 
   // Apply substitutions to the rendered output.
-  $element['output'] = array('#markup' => str_replace($search, $replace, drupal_render($element['output'])));
+  $element['output'] = array('#markup' => SafeMarkup::replace($search, $replace, drupal_render($element['output'])));
 
   // Sort, render and add remaining form fields.
   $children = Element::children($element, TRUE);
diff --git a/core/modules/views_ui/views_ui.theme.inc b/core/modules/views_ui/views_ui.theme.inc
index f2f2b67..4aafde4 100644
--- a/core/modules/views_ui/views_ui.theme.inc
+++ b/core/modules/views_ui/views_ui.theme.inc
@@ -147,21 +147,35 @@ function theme_views_ui_build_group_filter_form($variables) {
 
   foreach (Element::children($form['group_items']) as $group_id) {
     $form['group_items'][$group_id]['value']['#title'] = '';
+    $default = array(
+      $form['default_group'][$group_id],
+      $form['default_group_multiple'][$group_id],
+    );
+    $link = [
+      '#type' => 'link',
+      '#url' => Url::fromRoute('<none>', [], [
+        'attributes' => [
+          'id' => 'views-remove-link-' . $group_id,
+          'class' => [
+            'views-hidden',
+            'views-button-remove',
+            'views-groups-remove-link',
+            'views-remove-link',
+          ],
+          'alt' => t('Remove this item'),
+          'title' => t('Remove this item'),
+        ],
+      ]),
+      '#title' => SafeMarkup::format('<span>@text</span>', ['@text' => t('Remove')]),
+    ];
+    $remove = [$form['group_items'][$group_id]['remove'], $link];
     $data = array(
-      'default' => array(
-        'data' => array(
-          '#markup' => drupal_render($form['default_group'][$group_id]) . drupal_render($form['default_group_multiple'][$group_id]),
-        ),
-      ),
+      'default' => ['data' => $default],
       'weight' => drupal_render($form['group_items'][$group_id]['weight']),
       'title' => drupal_render($form['group_items'][$group_id]['title']),
       'operator' => drupal_render($form['group_items'][$group_id]['operator']),
       'value' => drupal_render($form['group_items'][$group_id]['value']),
-      'remove' => array(
-        'data' => array(
-          '#markup' => drupal_render($form['group_items'][$group_id]['remove']) . \Drupal::l(SafeMarkup::format('<span>@text</span>', array('@text' => t('Remove'))), Url::fromRoute('<none>', [], array('attributes' => array('id' => 'views-remove-link-' . $group_id, 'class' => array('views-hidden', 'views-button-remove', 'views-groups-remove-link', 'views-remove-link'), 'alt' => t('Remove this item'), 'title' => t('Remove this item'))))),
-        ),
-      ),
+      'remove' => ['data' => $remove],
     );
     $rows[] = array('data' => $data, 'id' => 'views-row-' . $group_id, 'class' => array('draggable'));
   }
diff --git a/core/tests/Drupal/Tests/Component/Utility/SafeMarkupTest.php b/core/tests/Drupal/Tests/Component/Utility/SafeMarkupTest.php
index 1e7d355..acba34a 100644
--- a/core/tests/Drupal/Tests/Component/Utility/SafeMarkupTest.php
+++ b/core/tests/Drupal/Tests/Component/Utility/SafeMarkupTest.php
@@ -188,4 +188,73 @@ function testPlaceholder() {
     $this->assertEquals('<em class="placeholder">Some text</em>', SafeMarkup::placeholder('Some text'));
   }
 
+  /**
+   * Tests SafeMarkup::replace().
+   *
+   * @dataProvider providerReplace
+   * @covers ::replace
+   */
+  public function testReplaces($search, $replace, $subject, $expected, $is_safe) {
+    $result = SafeMarkup::replace($search, $replace, $subject);
+    $this->assertEquals($expected, $result);
+    $this->assertEquals($is_safe, SafeMarkup::isSafe($result));
+  }
+
+  /**
+   * Data provider for testReplace().
+   *
+   * @see testReplace()
+   */
+  public function providerReplace() {
+    $tests = [];
+
+    // Subject unsafe.
+    $tests[] = [
+      '<placeholder>',
+      SafeMarkup::set('foo'),
+      '<placeholder>bazqux',
+      'foobazqux',
+      FALSE,
+    ];
+
+    // All safe.
+    $tests[] = [
+      '<placeholder>',
+      SafeMarkup::set('foo'),
+      SafeMarkup::set('<placeholder>barbaz'),
+      'foobarbaz',
+      TRUE,
+    ];
+
+    // Safe subject, but should result in unsafe string because replacement is
+    // unsafe.
+    $tests[] = [
+      '<placeholder>',
+      'fubar',
+      SafeMarkup::set('<placeholder>barbaz'),
+      'fubarbarbaz',
+      FALSE,
+    ];
+
+    // Array with all safe.
+    $tests[] = [
+      ['<placeholder1>', '<placeholder2>', '<placeholder3>'],
+      [SafeMarkup::set('foo'), SafeMarkup::set('bar'), SafeMarkup::set('baz')],
+      SafeMarkup::set('<placeholder1><placeholder2><placeholder3>'),
+      'foobarbaz',
+      TRUE,
+    ];
+
+    // Array with unsafe replacement.
+    $tests[] = [
+      ['<placeholder1>', '<placeholder2>', '<placeholder3>',],
+      [SafeMarkup::set('bar'), SafeMarkup::set('baz'), 'qux'],
+      SafeMarkup::set('<placeholder1><placeholder2><placeholder3>'),
+      'barbazqux',
+      FALSE,
+    ];
+
+    return $tests;
+  }
+
 }
diff --git a/core/tests/Drupal/Tests/Core/Render/RendererPostRenderCacheTest.php b/core/tests/Drupal/Tests/Core/Render/RendererPostRenderCacheTest.php
index 50ccc2e..d96e4fd 100644
--- a/core/tests/Drupal/Tests/Core/Render/RendererPostRenderCacheTest.php
+++ b/core/tests/Drupal/Tests/Core/Render/RendererPostRenderCacheTest.php
@@ -432,7 +432,7 @@ public function testPlaceholder() {
       '#prefix' => '<pre>',
       '#suffix' => '</pre>',
     ];
-    $expected_output = '<pre><bar>' . $context['bar'] . '</bar></pre>';
+    $expected_output = '<pre><code>' . $context['bar'] . '</code></pre>';
 
     // #cache disabled.
     $element = $test_element;
@@ -530,7 +530,7 @@ public function testChildElementPlaceholder() {
         '#suffix' => '</pre>'
       ],
     ];
-    $expected_output = '<pre><bar>' . $context['bar'] . '</bar></pre>' . "\n";
+    $expected_output = '<pre><code>' . $context['bar'] . '</code></pre>' . "\n";
 
     // #cache disabled.
     $element = $test_element;
diff --git a/core/tests/Drupal/Tests/Core/Render/RendererTest.php b/core/tests/Drupal/Tests/Core/Render/RendererTest.php
index e8368b2..addfa4b 100644
--- a/core/tests/Drupal/Tests/Core/Render/RendererTest.php
+++ b/core/tests/Drupal/Tests/Core/Render/RendererTest.php
@@ -81,6 +81,10 @@ public function providerTestRenderBasic() {
     $data[] = [[
       'child' => ['#markup' => 'bar'],
     ], 'bar'];
+    // XSS filtering test.
+    $data[] = [[
+      'child' => ['#markup' => "This is <script>alert('XSS')</script> test"],
+    ], "This is alert('XSS') test"];
     // #children set but empty, and renderable children.
     $data[] = [[
       '#children' => '',
diff --git a/core/tests/Drupal/Tests/Core/Render/RendererTestBase.php b/core/tests/Drupal/Tests/Core/Render/RendererTestBase.php
index 903adce..fb0aeb9 100644
--- a/core/tests/Drupal/Tests/Core/Render/RendererTestBase.php
+++ b/core/tests/Drupal/Tests/Core/Render/RendererTestBase.php
@@ -255,7 +255,7 @@ public static function callback(array $element, array $context) {
   public static function placeholder(array $element, array $context) {
     $placeholder = \Drupal::service('renderer')->generateCachePlaceholder(__NAMESPACE__ . '\\PostRenderCache::placeholder', $context);
     $replace_element = array(
-      '#markup' => '<bar>' . $context['bar'] . '</bar>',
+      '#markup' => '<code>' . $context['bar'] . '</code>',
       '#attached' => array(
         'drupalSettings' => [
           'common_test' => $context,