diff --git a/core/core.services.yml b/core/core.services.yml
index 0b8be53..8271f84 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -189,7 +189,7 @@ services:
     arguments: ['%container.modules%', '@state', '@cache.bootstrap']
   theme_handler:
     class: Drupal\Core\Extension\ThemeHandler
-    arguments: ['@config.factory', '@module_handler', '@cache.default', '@info_parser', '@config.installer', '@router.builder']
+    arguments: ['@config.factory', '@module_handler', '@state', '@info_parser', '@config.installer', '@router.builder']
   entity.manager:
     class: Drupal\Core\Entity\EntityManager
     arguments: ['@container.namespaces', '@service_container', '@module_handler', '@cache.default', '@language_manager', '@string_translation']
diff --git a/core/includes/module.inc b/core/includes/module.inc
index c219eaf..cbbe811 100644
--- a/core/includes/module.inc
+++ b/core/includes/module.inc
@@ -32,13 +32,9 @@ function system_list($type) {
       'theme' => array(),
       'filepaths' => array(),
     );
-    $enabled_themes = \Drupal::config('core.extension')->get('theme') ?: array();
-    // system_rebuild_theme_data() allows modules to alter the info of all
-    // themes, so we are not able to simply consume the system.theme.data state
-    // record here.
-    $theme_data = system_rebuild_theme_data();
+    // ThemeHandler maintains the 'system.theme.data' state record.
+    $theme_data = \Drupal::state()->get('system.theme.data', array());
     foreach ($theme_data as $name => $theme) {
-      $theme->status = (int) isset($enabled_themes[$name]);
       $lists['theme'][$name] = $theme;
       $lists['filepaths'][] = array(
         'type' => 'theme',
diff --git a/core/lib/Drupal/Core/DependencyInjection/UpdateServiceProvider.php b/core/lib/Drupal/Core/DependencyInjection/UpdateServiceProvider.php
index aa3c709..aaceae9 100644
--- a/core/lib/Drupal/Core/DependencyInjection/UpdateServiceProvider.php
+++ b/core/lib/Drupal/Core/DependencyInjection/UpdateServiceProvider.php
@@ -43,7 +43,7 @@ public function register(ContainerBuilder $container) {
       $container->register('theme_handler', 'Drupal\Core\Extension\ThemeHandler')
         ->addArgument(new Reference('config.factory'))
         ->addArgument(new Reference('module_handler'))
-        ->addArgument(new Reference('cache.default'))
+        ->addArgument(new Reference('state'))
         ->addArgument(new Reference('info_parser'));
     }
   }
diff --git a/core/lib/Drupal/Core/Extension/ModuleHandler.php b/core/lib/Drupal/Core/Extension/ModuleHandler.php
index 17b4239..5831024 100644
--- a/core/lib/Drupal/Core/Extension/ModuleHandler.php
+++ b/core/lib/Drupal/Core/Extension/ModuleHandler.php
@@ -650,8 +650,6 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
 
         // Refresh the schema to include it.
         drupal_get_schema(NULL, TRUE);
-        // Update the theme registry to include it.
-        drupal_theme_rebuild();
 
         // Allow modules to react prior to the installation of a module.
         $this->invokeAll('module_preinstall', array($module));
@@ -684,8 +682,18 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
         // Record the fact that it was installed.
         $modules_installed[] = $module;
 
+        // Update the theme registry to include it.
+        drupal_theme_rebuild();
+
+        // Modules can alter theme info, so refresh theme data.
+        // @todo ThemeHandler cannot be injected into ModuleHandler, since that
+        //   causes a circular service dependency.
+        // @see https://drupal.org/node/2208429
+        \Drupal::service('theme_handler')->refreshInfo();
+
         // Allow the module to perform install tasks.
         $this->invoke($module, 'install');
+
         // Record the fact that it was installed.
         watchdog('system', '%module module installed.', array('%module' => $module), WATCHDOG_INFO);
       }
@@ -792,6 +800,12 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
       // Update the theme registry to remove the newly uninstalled module.
       drupal_theme_rebuild();
 
+      // Modules can alter theme info, so refresh theme data.
+      // @todo ThemeHandler cannot be injected into ModuleHandler, since that
+      //   causes a circular service dependency.
+      // @see https://drupal.org/node/2208429
+      \Drupal::service('theme_handler')->refreshInfo();
+
       watchdog('system', '%module module uninstalled.', array('%module' => $module), WATCHDOG_INFO);
 
       $schema_store->delete($module);
diff --git a/core/lib/Drupal/Core/Extension/ThemeHandler.php b/core/lib/Drupal/Core/Extension/ThemeHandler.php
index 07645a6..593a0b7 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandler.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandler.php
@@ -9,9 +9,9 @@
 
 use Drupal\Component\Utility\String;
 use Drupal\Core\Cache\Cache;
-use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Config\ConfigInstallerInterface;
+use Drupal\Core\KeyValueStore\StateInterface;
 use Drupal\Core\Routing\RouteBuilder;
 
 /**
@@ -58,11 +58,11 @@ class ThemeHandler implements ThemeHandlerInterface {
   protected $moduleHandler;
 
   /**
-   * The cache backend to clear the local tasks cache.
+   * The state backend.
    *
-   * @var \Drupal\Core\Cache\CacheBackendInterface
+   * @var \Drupal\Core\KeyValueStore\StateInterface
    */
-  protected $cacheBackend;
+  protected $state;
 
   /**
    *  The config installer to install configuration.
@@ -99,7 +99,7 @@ class ThemeHandler implements ThemeHandlerInterface {
    *   The config factory to get the enabled themes.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler to fire themes_enabled/themes_disabled hooks.
-   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
+   * @param \Drupal\Core\KeyValueStore\StateInterface $state
    *   The cache backend to clear the local tasks cache.
    * @param \Drupal\Core\Extension\InfoParserInterface $info_parser
    *   The info parser to parse the theme.info.yml files.
@@ -112,10 +112,10 @@ class ThemeHandler implements ThemeHandlerInterface {
    * @param \Drupal\Core\Extension\ExtensionDiscovery $extension_discovery
    *   (optional) A extension discovery instance (for unit tests).
    */
-  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, CacheBackendInterface $cache_backend, InfoParserInterface $info_parser, ConfigInstallerInterface $config_installer = NULL, RouteBuilder $route_builder = NULL, ExtensionDiscovery $extension_discovery = NULL) {
+  public function __construct(ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, StateInterface $state, InfoParserInterface $info_parser, ConfigInstallerInterface $config_installer = NULL, RouteBuilder $route_builder = NULL, ExtensionDiscovery $extension_discovery = NULL) {
     $this->configFactory = $config_factory;
     $this->moduleHandler = $module_handler;
-    $this->cacheBackend = $cache_backend;
+    $this->state = $state;
     $this->infoParser = $info_parser;
     $this->configInstaller = $config_installer;
     $this->routeBuilder = $route_builder;
@@ -151,7 +151,7 @@ public function setDefault($name) {
   public function enable(array $theme_list, $enable_dependencies = TRUE) {
     $extension_config = $this->configFactory->get('core.extension');
 
-    $theme_data = system_rebuild_theme_data();
+    $theme_data = $this->rebuildThemeData();
 
     if ($enable_dependencies) {
       $theme_list = array_combine($theme_list, $theme_list);
@@ -220,10 +220,11 @@ public function enable(array $theme_list, $enable_dependencies = TRUE) {
         ->save();
 
       // Update the current theme data accordingly.
-      // @todo Inject State service.
-      $current_theme_data = \Drupal::state()->get('system.theme.data', array());
+      // @todo Remove all code that relies on $status property.
+      $theme_data[$key]->status = 1;
+      $current_theme_data = $this->state->get('system.theme.data', array());
       $current_theme_data[$key] = $theme_data[$key];
-      \Drupal::state()->set('system.theme.data', $current_theme_data);
+      $this->state->set('system.theme.data', $current_theme_data);
 
       $theme_settings = &drupal_static('theme_get_setting');
       unset($theme_settings[$key]);
@@ -267,7 +268,7 @@ public function disable(array $theme_list) {
     $this->clearCssCache();
 
     $extension_config = $this->configFactory->get('core.extension');
-    $current_theme_data = \Drupal::state()->get('system.theme.data', array());
+    $current_theme_data = $this->state->get('system.theme.data', array());
     foreach ($theme_list as $key) {
       // The value is not used; the weight is ignored for themes currently.
       $extension_config
@@ -280,7 +281,7 @@ public function disable(array $theme_list) {
       unset($theme_settings[$key]);
     }
     $extension_config->save();
-    \Drupal::state()->set('system.theme.data', $current_theme_data);
+    $this->state->set('system.theme.data', $current_theme_data);
 
     $this->reset();
     $this->resetSystem();
@@ -328,6 +329,25 @@ public function addTheme(Extension $theme) {
   /**
    * {@inheritdoc}
    */
+  public function refreshInfo() {
+    $this->reset();
+    $extension_config = $this->configFactory->get('core.extension');
+    $enabled = $extension_config->get('theme') ?: array();
+
+    // @todo Avoid re-scanning all themes by retaining the original (unaltered)
+    //   theme info somewhere.
+    $list = $this->rebuildThemeData();
+    foreach ($list as $name => $theme) {
+      if (isset($enabled[$name])) {
+        $this->list[$name] = $theme;
+      }
+    }
+    $this->state->set('system.theme.data', $this->list);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function reset() {
     $this->systemListReset();
     $this->list = NULL;
@@ -340,6 +360,8 @@ public function rebuildThemeData() {
     $listing = $this->getExtensionDiscovery();
     $themes = $listing->scan('theme');
     $engines = $listing->scan('theme_engine');
+    $extension_config = $this->configFactory->get('core.extension');
+    $enabled = $extension_config->get('theme') ?: array();
 
     // Set defaults for theme info.
     $defaults = array(
@@ -364,8 +386,12 @@ public function rebuildThemeData() {
     );
 
     $sub_themes = array();
+    $files = array();
     // Read info files for each theme.
     foreach ($themes as $key => $theme) {
+      // @todo Remove all code that relies on the $status property.
+      $theme->status = (int) isset($enabled[$key]);
+
       $theme->info = $this->infoParser->parse($theme->getPathname()) + $defaults;
 
       // Add the info file modification time, so it becomes available for
@@ -397,7 +423,17 @@ public function rebuildThemeData() {
       if (!empty($theme->info['screenshot'])) {
         $theme->info['screenshot'] = $path . '/' . $theme->info['screenshot'];
       }
+
+      $files[$key] = $theme->getPathname();
     }
+    // Build dependencies.
+    // @todo Move into a generic ExtensionHandler base class.
+    // @see https://drupal.org/node/2208429
+    $themes = $this->moduleHandler->buildModuleDependencies($themes);
+
+    // Store filenames to allow system_list() and drupal_get_filename() to
+    // retrieve them without having to scan the filesystem.
+    $this->state->set('system.theme.files', $files);
 
     // After establishing the full list of available themes, fill in data for
     // sub-themes.
diff --git a/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php b/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
index 92ab92f..fbf57fd 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
@@ -77,6 +77,14 @@ public function disable(array $theme_list);
   public function listInfo();
 
   /**
+   * Refreshes the theme info data of currently enabled themes.
+   *
+   * Modules can alter theme info, so this is typically called after a module
+   * has been installed or uninstalled.
+   */
+  public function refreshInfo();
+
+  /**
    * Resets the internal state of the theme handler.
    */
   public function reset();
diff --git a/core/modules/system/lib/Drupal/system/Tests/Extension/ThemeHandlerTest.php b/core/modules/system/lib/Drupal/system/Tests/Extension/ThemeHandlerTest.php
new file mode 100644
index 0000000..0268f7d
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/Extension/ThemeHandlerTest.php
@@ -0,0 +1,298 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Extension\ThemeHandlerTest.
+ */
+
+namespace Drupal\system\Tests\Extension;
+
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\simpletest\DrupalUnitTestBase;
+
+/**
+ * Tests installing/enabling, disabling, and uninstalling of themes.
+ */
+class ThemeHandlerTest extends DrupalUnitTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('system');
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Theme handler',
+      'description' => 'Tests installing/enabling, disabling, and uninstalling of themes.',
+      'group' => 'Extension',
+    );
+  }
+
+  public function containerBuild(ContainerBuilder $container) {
+    parent::containerBuild($container);
+    // Some test methods involve ModuleHandler operations, which attempt to
+    // rebuild and dump routes.
+    $container
+      ->register('router.dumper', 'Drupal\Core\Routing\NullMatcherDumper');
+  }
+
+  function setUp() {
+    parent::setUp();
+    $this->installConfig(array('system'));
+  }
+
+  /**
+   * Verifies that no themes are installed/enabled/disabled by default.
+   */
+  function testEmpty() {
+    $this->assertFalse($this->extensionConfig()->get('theme'));
+    $this->assertFalse($this->extensionConfig()->get('disabled.theme'));
+
+    $this->assertFalse(array_keys($this->themeHandler()->listInfo()));
+    $this->assertFalse(array_keys(system_list('theme')));
+
+    // Rebuilding available themes should always yield results though.
+    $this->assertTrue($this->themeHandler()->rebuildThemeData()['stark'], 'ThemeHandler::rebuildThemeData() yields all available themes.');
+    $this->assertTrue(system_rebuild_theme_data()['stark'], 'system_rebuild_theme_data() yields all available themes.');
+
+    // theme_get_setting() should return global default theme settings.
+    $this->assertIdentical(theme_get_setting('features.favicon'), TRUE);
+  }
+
+  /**
+   * Tests enabling a theme.
+   */
+  function testEnable() {
+    $name = 'test_basetheme';
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertFalse(isset($themes[$name]));
+
+    $this->themeHandler()->enable(array($name));
+
+    $this->assertIdentical($this->extensionConfig()->get("theme.$name"), 0);
+    $this->assertFalse($this->extensionConfig()->get("disabled.theme.$name"));
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertTrue(isset($themes[$name]));
+    $this->assertEqual($themes[$name]->getName(), $name);
+
+    $this->assertEqual(array_keys(system_list('theme')), array_keys($themes));
+
+    // Verify that test_basetheme.settings is active.
+    $this->assertIdentical(theme_get_setting('features.favicon', $name), FALSE);
+    $this->assertEqual(theme_get_setting('base', $name), 'only');
+    $this->assertEqual(theme_get_setting('override', $name), 'base');
+  }
+
+  /**
+   * Tests enabling a sub-theme.
+   */
+  function testEnableSubTheme() {
+    $name = 'test_subtheme';
+    $base_name = 'test_basetheme';
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertFalse(array_keys($themes));
+
+    $this->themeHandler()->enable(array($name));
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertTrue(isset($themes[$name]));
+    $this->assertTrue(isset($themes[$base_name]));
+
+    $this->themeHandler()->disable(array($name));
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertFalse(isset($themes[$name]));
+    $this->assertTrue(isset($themes[$base_name]));
+  }
+
+  /**
+   * Tests disabling a theme.
+   */
+  function testDisable() {
+    $name = 'test_basetheme';
+    $this->themeHandler()->enable(array($name));
+
+    // Prime the relevant drupal_static()s.
+    $this->assertEqual(array_keys(system_list('theme')), array($name));
+    $this->assertIdentical(theme_get_setting('features.favicon', $name), FALSE);
+
+    $this->themeHandler()->disable(array($name));
+
+    $this->assertIdentical($this->extensionConfig()->get('theme'), array());
+    $this->assertIdentical($this->extensionConfig()->get("disabled.theme.$name"), 0);
+
+    $this->assertFalse(array_keys($this->themeHandler()->listInfo()));
+    $this->assertFalse(array_keys(system_list('theme')));
+
+    // Verify that test_basetheme.settings no longer applies, even though the
+    // configuration still exists.
+    $this->assertIdentical(theme_get_setting('features.favicon', $name), TRUE);
+    $this->assertNull(theme_get_setting('base', $name));
+    $this->assertNull(theme_get_setting('override', $name));
+
+    // The theme is not uninstalled, so its configuration must still exist.
+    $this->assertTrue($this->config("$name.settings")->get());
+  }
+
+  /**
+   * Tests disabling and enabling a theme.
+   */
+  function testDisableEnable() {
+    $name = 'test_basetheme';
+    $this->testDisable();
+    $this->config("$name.settings")->set('keep', 'me')->save();
+
+    $this->testEnable();
+    $this->assertIdentical($this->config("$name.settings")->get('keep'), 'me');
+  }
+
+  /**
+   * Tests disabling the default theme.
+   */
+  function testDisableDefault() {
+    $name = 'stark';
+    $other_name = 'bartik';
+    $this->themeHandler()->enable(array($name, $other_name));
+    $this->themeHandler()->setDefault($name);
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertTrue(isset($themes[$name]));
+    $this->assertTrue(isset($themes[$other_name]));
+
+    try {
+      $message = 'ThemeHandler::disable() throws InvalidArgumentException upon disabling default theme.';
+      $this->themeHandler()->disable(array($name));
+      $this->fail($message);
+    }
+    catch (\InvalidArgumentException $e) {
+      $this->pass($message);
+    }
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertTrue(isset($themes[$name]));
+    $this->assertTrue(isset($themes[$other_name]));
+  }
+
+  /**
+   * Tests disabling the admin theme.
+   */
+  function testDisableAdmin() {
+    $name = 'stark';
+    $other_name = 'bartik';
+    $this->themeHandler()->enable(array($name, $other_name));
+    $this->config('system.theme')->set('admin', $name)->save();
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertTrue(isset($themes[$name]));
+    $this->assertTrue(isset($themes[$other_name]));
+
+    try {
+      $message = 'ThemeHandler::disable() throws InvalidArgumentException upon disabling admin theme.';
+      $this->themeHandler()->disable(array($name));
+      $this->fail($message);
+    }
+    catch (\InvalidArgumentException $e) {
+      $this->pass($message);
+    }
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertTrue(isset($themes[$name]));
+    $this->assertTrue(isset($themes[$other_name]));
+  }
+
+  /**
+   * Tests disabling a sub-theme.
+   */
+  function testDisableSubTheme() {
+    $name = 'test_subtheme';
+    $base_name = 'test_basetheme';
+
+    $this->themeHandler()->enable(array($name));
+    $this->themeHandler()->disable(array($name));
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertFalse(isset($themes[$name]));
+    $this->assertTrue(isset($themes[$base_name]));
+  }
+
+  /**
+   * Tests that theme info can be altered by a module.
+   *
+   * @see module_test_system_info_alter()
+   */
+  function testThemeInfoAlter() {
+    $name = 'seven';
+    $this->container->get('state')->set('module_test.hook_system_info_alter', TRUE);
+    $module_handler = $this->container->get('module_handler');
+
+    $this->themeHandler()->enable(array($name));
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertFalse(isset($themes[$name]->info['regions']['test_region']));
+
+    $module_handler->install(array('module_test'), FALSE);
+    $this->assertTrue($module_handler->moduleExists('module_test'));
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertTrue(isset($themes[$name]->info['regions']['test_region']));
+
+    // Legacy assertions.
+    // @todo Remove once theme initialization/info has been modernized.
+    // @see https://drupal.org/node/2228093
+    $info = system_get_info('theme', $name);
+    $this->assertTrue(isset($info['regions']['test_region']));
+    $regions = system_region_list($name);
+    $this->assertTrue(isset($regions['test_region']));
+    $system_list = system_list('theme');
+    $this->assertTrue(isset($system_list[$name]->info['regions']['test_region']));
+
+    $module_handler->uninstall(array('module_test'));
+    $this->assertFalse($module_handler->moduleExists('module_test'));
+
+    $themes = $this->themeHandler()->listInfo();
+    $this->assertFalse(isset($themes[$name]->info['regions']['test_region']));
+
+    // Legacy assertions.
+    // @todo Remove once theme initialization/info has been modernized.
+    // @see https://drupal.org/node/2228093
+    $info = system_get_info('theme', $name);
+    $this->assertFalse(isset($info['regions']['test_region']));
+    $regions = system_region_list($name);
+    $this->assertFalse(isset($regions['test_region']));
+    $system_list = system_list('theme');
+    $this->assertFalse(isset($system_list[$name]->info['regions']['test_region']));
+  }
+
+  /**
+   * Returns the theme handler service.
+   *
+   * @return \Drupal\Core\Extension\ThemeHandlerInterface
+   */
+  protected function themeHandler() {
+    return $this->container->get('theme_handler');
+  }
+
+  /**
+   * Returns the system.theme config object.
+   *
+   * @return \Drupal\Core\Config\Config
+   */
+  protected function extensionConfig() {
+    return $this->config('core.extension');
+  }
+
+  /**
+   * Returns a given config object.
+   *
+   * @return \Drupal\Core\Config\Config
+   */
+  protected function config($name) {
+    return $this->container->get('config.factory')->get($name);
+  }
+
+}
diff --git a/core/modules/system/lib/Drupal/system/Tests/Extension/ThemeInstallTest.php b/core/modules/system/lib/Drupal/system/Tests/Extension/ThemeInstallTest.php
deleted file mode 100644
index 4bb5418..0000000
--- a/core/modules/system/lib/Drupal/system/Tests/Extension/ThemeInstallTest.php
+++ /dev/null
@@ -1,145 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\system\Tests\Extension\ThemeInstallTest.
- */
-
-namespace Drupal\system\Tests\Extension;
-
-use Drupal\simpletest\DrupalUnitTestBase;
-
-/**
- * Tests installing/enabling, disabling, and uninstalling of themes.
- */
-class ThemeInstallTest extends DrupalUnitTestBase {
-
-  /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = array('system');
-
-  public static function getInfo() {
-    return array(
-      'name' => 'Theme installation',
-      'description' => 'Tests installing/enabling, disabling, and uninstalling of themes.',
-      'group' => 'Extension',
-    );
-  }
-
-  function setUp() {
-    parent::setUp();
-    $this->installConfig(array('system'));
-  }
-
-  /**
-   * Verifies that no themes are installed/enabled/disabled by default.
-   */
-  function testEmpty() {
-    $this->assertFalse($this->extensionConfig()->get('theme'));
-    $this->assertFalse($this->extensionConfig()->get('disabled.theme'));
-
-    $this->assertFalse($this->themeHandler()->listInfo());
-    $this->assertFalse(system_list('theme'));
-
-    // Rebuilding available themes should always yield results though.
-    $this->assertTrue($this->themeHandler()->rebuildThemeData()['stark'], 'ThemeHandler::rebuildThemeData() yields all available themes.');
-    $this->assertTrue(system_rebuild_theme_data()['stark'], 'system_rebuild_theme_data() yields all available themes.');
-
-    // theme_get_setting() should return global default theme settings.
-    $this->assertIdentical(theme_get_setting('features.favicon'), TRUE);
-  }
-
-  /**
-   * Tests enabling a theme.
-   */
-  function testEnable() {
-    $name = 'test_basetheme';
-    $this->themeHandler()->enable(array($name));
-
-    $this->assertIdentical($this->extensionConfig()->get("theme.$name"), 0);
-    $this->assertFalse($this->extensionConfig()->get("disabled.theme.$name"));
-
-    $list = $this->themeHandler()->listInfo();
-    $this->assertTrue(isset($list[$name]));
-    $this->assertEqual($list[$name]->getName(), $name);
-
-    $this->assertEqual(array_keys(system_list('theme')), array_keys($list));
-
-    // Verify that test_basetheme.settings is active.
-    $this->assertIdentical(theme_get_setting('features.favicon', $name), FALSE);
-    $this->assertEqual(theme_get_setting('base', $name), 'only');
-    $this->assertEqual(theme_get_setting('override', $name), 'base');
-  }
-
-  /**
-   * Tests disabling a theme.
-   */
-  function testDisable() {
-    $name = 'test_basetheme';
-    $this->themeHandler()->enable(array($name));
-
-    // Prime the relevant drupal_static()s.
-    $this->assertEqual(array_keys(system_list('theme')), array($name));
-    $this->assertIdentical(theme_get_setting('features.favicon', $name), FALSE);
-
-    $this->themeHandler()->disable(array($name));
-
-    $this->assertIdentical($this->extensionConfig()->get('theme'), array());
-    $this->assertIdentical($this->extensionConfig()->get("disabled.theme.$name"), 0);
-
-    $this->assertFalse($this->themeHandler()->listInfo());
-    $this->assertFalse(system_list('theme'));
-
-    // Verify that test_basetheme.settings no longer applies, even though the
-    // configuration still exists.
-    $this->assertIdentical(theme_get_setting('features.favicon', $name), TRUE);
-    $this->assertNull(theme_get_setting('base', $name));
-    $this->assertNull(theme_get_setting('override', $name));
-
-    // The theme is not uninstalled, so its configuration must still exist.
-    $this->assertTrue($this->config("$name.settings")->get());
-  }
-
-  /**
-   * Tests disabling and enabling a theme.
-   */
-  function testDisableEnable() {
-    $name = 'test_basetheme';
-    $this->testDisable();
-    $this->config("$name.settings")->set('keep', 'me')->save();
-
-    $this->testEnable();
-    $this->assertIdentical($this->config("$name.settings")->get('keep'), 'me');
-  }
-
-  /**
-   * Returns the theme handler service.
-   *
-   * @return \Drupal\Core\Extension\ThemeHandlerInterface
-   */
-  protected function themeHandler() {
-    return $this->container->get('theme_handler');
-  }
-
-  /**
-   * Returns the system.theme config object.
-   *
-   * @return \Drupal\Core\Config\Config
-   */
-  protected function extensionConfig() {
-    return $this->config('core.extension');
-  }
-
-  /**
-   * Returns a given config object.
-   *
-   * @return \Drupal\Core\Config\Config
-   */
-  protected function config($name) {
-    return $this->container->get('config.factory')->get($name);
-  }
-
-}
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/InfoAlterTest.php b/core/modules/system/lib/Drupal/system/Tests/System/InfoAlterTest.php
index b57d44e..31387d0 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/InfoAlterTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/InfoAlterTest.php
@@ -36,25 +36,10 @@ function testSystemInfoAlter() {
     $info = system_rebuild_module_data();
     $this->assertFalse(isset($info['node']->info['required']), 'Before the module_test is installed the node module is not required.');
 
-    // Enable seven and the test module.
-    theme_enable(array('seven'));
+    // Enable the test module.
     \Drupal::moduleHandler()->install(array('module_test'), FALSE);
     $this->assertTrue(\Drupal::moduleHandler()->moduleExists('module_test'), 'Test module is enabled.');
 
-    // Verify that the rebuilt and altered theme info is returned.
-    $info = system_get_info('theme', 'seven');
-    $this->assertTrue(isset($info['regions']['test_region']), 'Altered theme info was returned by system_get_info().');
-
-    $seven_regions = system_region_list('seven');
-    $this->assertTrue(isset($seven_regions['test_region']), 'Altered theme info was returned by system_region_list().');
-
-    $system_list_themes = system_list('theme');
-    $info = $system_list_themes['seven']->info;
-    $this->assertTrue(isset($info['regions']['test_region']), 'Altered theme info was returned by system_list().');
-
-    $list_themes = list_themes();
-    $this->assertTrue(isset($list_themes['seven']->info['regions']['test_region']), 'Altered theme info was returned by list_themes().');
-
     $info = system_rebuild_module_data();
     $this->assertTrue($info['node']->info['required'], 'After the module_test is installed the node module is required.');
   }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php b/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
index 1fab23b..9d34007 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
@@ -280,39 +280,4 @@ function testPreprocessHtml() {
     $this->assertText('theme test page bottom markup', 'Modules are able to set the page bottom region.');
   }
 
-  /**
-   * Test that themes can be disabled programmatically but admin theme and default theme can not.
-   */
-  function testDisableTheme() {
-    // Enable Bartik, Seven and Stark.
-    \Drupal::service('theme_handler')->enable(array('bartik', 'seven', 'stark'));
-
-    // Set Bartik as the default theme and Seven as the admin theme.
-    \Drupal::config('system.theme')
-      ->set('default', 'bartik')
-      ->set('admin', 'seven')
-      ->save();
-
-    $theme_list = \Drupal::service('theme_handler')->listInfo();
-    $this->assertTrue(isset($theme_list['bartik']), 'Default theme is enabled.');
-    $this->assertTrue(isset($theme_list['seven']), 'Admin theme is enabled.');
-    $this->assertTrue(isset($theme_list['stark']), 'Stark is enabled.');
-
-    // Attempt to disable all themes. theme_disable() ensures that the default
-    // theme and the admin theme cannot be disabled.
-    try {
-      \Drupal::service('theme_handler')->disable(array('bartik', 'seven', 'stark'));
-      $this->fail('ThemeHandler::disable() throws InvalidArgumentException when trying to disable the default or admin theme.');
-    }
-    catch (\InvalidArgumentException $e) {
-      $this->pass('ThemeHandler::disable() throws InvalidArgumentException when trying to disable the default or admin theme.');
-    }
-
-    $theme_list = \Drupal::service('theme_handler')->listInfo();
-
-    // Assert that all themes are still enabled.
-    $this->assertTrue(isset($theme_list['bartik']), 'Default theme is enabled.');
-    $this->assertTrue(isset($theme_list['seven']), 'Admin theme is enabled.');
-    $this->assertTrue(isset($theme_list['stark']), 'Stark is enabled.');
-  }
 }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Theme/TwigSettingsTest.php b/core/modules/system/lib/Drupal/system/Tests/Theme/TwigSettingsTest.php
index 5689b3d..c920f2a 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Theme/TwigSettingsTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Theme/TwigSettingsTest.php
@@ -77,24 +77,19 @@ function testTwigDebugOverride() {
    */
   function testTwigCacheOverride() {
     $extension = twig_extension();
-    theme_enable(array('test_theme'));
-    \Drupal::config('system.theme')
-      ->set('default', 'test_theme')
-      ->save();
-
-    // Unset the global variables, so \Drupal\Core\Theme\Registry::init() fires
-    // drupal_theme_initialize, which fills up the global variables  properly
-    // and chosen the current active theme.
-    unset($GLOBALS['theme_info']);
-    unset($GLOBALS['theme']);
-    // Reset the theme registry, so that the new theme is used.
-    $this->container->set('theme.registry', NULL);
+    $theme_handler = \Drupal::service('theme_handler');
+    $theme_handler->enable(array('test_theme'));
+    $theme_handler->setDefault('test_theme');
 
-    // Load array of Twig templates.
-    $registry = $this->container->get('theme.registry');
-    $registry->reset();
+    // The registry still works on theme globals, so set them here.
+    $GLOBALS['theme'] = 'test_theme';
+    $GLOBALS['theme_info'] = $theme_handler->listInfo()['test_theme'];
 
-    $templates = $registry->getRuntime();
+    // Null out the container's theme registry to clear its properties.
+    $this->container->set('theme.registry', NULL);
+    // Load Twig templates in a new theme registry. reset() is necessary to
+    // invalidate the caches tagged with 'theme_registry'.
+    $templates = $this->container->get('theme.registry')->reset()->getRuntime();
 
     // Get the template filename and the cache filename for
     // theme_test.template_test.html.twig.
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 5e2b12a..f47ce55 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1309,33 +1309,12 @@ function system_rebuild_module_data() {
  *
  * @return \Drupal\Core\Extension\Extension[]
  *   Array of all available themes and their data.
+ *
+ * @deprecated 8.x
+ *   Use \Drupal::service('theme_handler')->rebuildThemeData().
  */
 function system_rebuild_theme_data() {
-  $themes = \Drupal::service('theme_handler')->rebuildThemeData();
-  ksort($themes);
-
-  // Add human-readable name and status.
-  $enabled_themes = \Drupal::config('core.extension')->get('theme') ?: array();
-  $files = array();
-  foreach ($themes as $name => $theme) {
-    $files[$name] = $theme->getPathname();
-    $theme->status = (int) isset($enabled_themes[$name]);
-  }
-  // Build dependencies.
-  if ($themes) {
-    $themes = \Drupal::moduleHandler()->buildModuleDependencies($themes);
-  }
-
-  // Replace last known theme data state.
-  \Drupal::state()->set('system.theme.data', array_filter($themes, function (Extension $theme) {
-    return !empty($theme->status);
-  }));
-
-  // Store filenames to allow system_list() and drupal_get_filename() to
-  // retrieve them without having to rebuild or scan the filesystem.
-  \Drupal::state()->set('system.theme.files', $files);
-
-  return $themes;
+  return \Drupal::service('theme_handler')->rebuildThemeData();
 }
 
 /**
diff --git a/core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php b/core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php
index 04ea77e..a464ad2 100644
--- a/core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php
+++ b/core/tests/Drupal/Tests/Core/Extension/ThemeHandlerTest.php
@@ -11,6 +11,8 @@
 use Drupal\Core\Extension\InfoParser;
 use Drupal\Core\Extension\ThemeHandler;
 use Drupal\Core\Config\ConfigInstaller;
+use Drupal\Core\KeyValueStore\KeyValueMemoryFactory;
+use Drupal\Core\KeyValueStore\State;
 use Drupal\Tests\UnitTestCase;
 
 /**
@@ -38,11 +40,11 @@ class ThemeHandlerTest extends UnitTestCase {
   protected $infoParser;
 
   /**
-   * The mocked cache backend.
+   * The mocked state backend.
    *
-   * @var \Drupal\Core\Cache\CacheBackendInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\KeyValueStore\StateInterface|\PHPUnit_Framework_MockObject_MockObject
    */
-  protected $cacheBackend;
+  protected $state;
 
   /**
    * The mocked config factory.
@@ -104,7 +106,7 @@ protected function setUp() {
       ),
     ));
     $this->moduleHandler = $this->getMock('Drupal\Core\Extension\ModuleHandlerInterface');
-    $this->cacheBackend = $this->getMock('Drupal\Core\Cache\CacheBackendInterface');
+    $this->state = new State(new KeyValueMemoryFactory());
     $this->infoParser = $this->getMock('Drupal\Core\Extension\InfoParserInterface');
     $this->configInstaller = $this->getMock('Drupal\Core\Config\ConfigInstallerInterface');
     $this->routeBuilder = $this->getMockBuilder('Drupal\Core\Routing\RouteBuilder')
@@ -113,15 +115,16 @@ protected function setUp() {
     $this->extensionDiscovery = $this->getMockBuilder('Drupal\Core\Extension\ExtensionDiscovery')
       ->disableOriginalConstructor()
       ->getMock();
-    $this->themeHandler = new TestThemeHandler($this->configFactory, $this->moduleHandler, $this->cacheBackend, $this->infoParser, $this->configInstaller, $this->routeBuilder, $this->extensionDiscovery);
+    $this->themeHandler = new TestThemeHandler($this->configFactory, $this->moduleHandler, $this->state, $this->infoParser, $this->configInstaller, $this->routeBuilder, $this->extensionDiscovery);
 
-    $this->getContainerWithCacheBins($this->cacheBackend);
+    $cache_backend = $this->getMock('Drupal\Core\Cache\CacheBackendInterface');
+    $this->getContainerWithCacheBins($cache_backend);
   }
 
   /**
    * Tests enabling a theme with a name longer than 50 chars.
    *
-   * @requires function system_rebuild_theme_data
+   * @requires function system__too_much_mocking
    *
    * @expectedException \Drupal\Core\Extension\ExtensionNameLengthException
    * @expectedExceptionMessage Theme name <em class="placeholder">thisNameIsFarTooLong0000000000000000000000000000051</em> is over the maximum allowed length of 50 characters.
@@ -133,7 +136,7 @@ public function testThemeEnableWithTooLongName() {
   /**
    * Tests enabling a single theme.
    *
-   * @requires function system_rebuild_theme_data
+   * @requires function system__too_much_mocking
    *
    * @see \Drupal\Core\Extension\ThemeHandler::enable()
    */
@@ -181,7 +184,7 @@ public function testEnableSingleTheme() {
   /**
    * Ensures that enabling a theme does clear the theme info listing.
    *
-   * @requires function system_rebuild_theme_data
+   * @requires function system__too_much_mocking
    *
    * @see \Drupal\Core\Extension\ThemeHandler::listInfo()
    */