diff --git a/core/includes/module.inc b/core/includes/module.inc
index 429f5db..b45f447 100644
--- a/core/includes/module.inc
+++ b/core/includes/module.inc
@@ -11,7 +11,7 @@
  *
  * @param $type
  *   The type of list to return:
- *   - module_enabled: All enabled modules.
+ *   - module: All enabled modules.
  *   - bootstrap: All enabled modules required for bootstrap.
  *   - theme: All themes.
  *
@@ -40,30 +40,26 @@ function system_list($type) {
     );
     // Build a list of themes.
     $enabled_themes = (array) \Drupal::config('system.theme')->get('enabled');
-    // @todo Themes include all themes, including disabled/uninstalled. This
-    //   system.theme.data state will go away entirely as soon as themes have
-    //   a proper installation status.
-    // @see http://drupal.org/node/1067408
-    $theme_data = \Drupal::state()->get('system.theme.data');
-    if (empty($theme_data)) {
-      // @todo: system_list() may be called from _drupal_bootstrap_code(), in
+    array_walk($enabled_themes, function (&$value, $key) {
+      $value = 'system.theme.data.' . $key;
+    });
+    $theme_data = (array) \Drupal::state()->getMultiple($enabled_themes);
+    // @todo Remove me?
+    if (0 && empty($theme_data)) {
+      // system_list() may be called from _drupal_bootstrap_code() and
       // which case system.module is not loaded yet.
       // Prevent a filesystem scan in drupal_load() and include it directly.
-      // @see http://drupal.org/node/1067408
       require_once DRUPAL_ROOT . '/core/modules/system/system.module';
       $theme_data = system_rebuild_theme_data();
     }
     foreach ($theme_data as $name => $theme) {
-      $theme->status = (int) isset($enabled_themes[$name]);
       $lists['theme'][$name] = $theme;
       // Build a list of filenames so drupal_get_filename can use it.
-      if (isset($enabled_themes[$name])) {
-        $lists['filepaths'][] = array(
-          'type' => 'theme',
-          'name' => $name,
-          'filepath' => $theme->filename,
-        );
-      }
+      $lists['filepaths'][] = array(
+        'type' => 'theme',
+        'name' => $name,
+        'filepath' => $theme->filename,
+      );
     }
     // @todo Move into list_themes(). Read info for a particular requested
     //   theme from state instead.
@@ -112,14 +108,12 @@ function system_list_reset() {
   drupal_static_reset('list_themes');
   cache('bootstrap')->delete('system_list');
   cache()->delete('system_info');
-  // Remove last known theme data state.
-  // This causes system_list() to call system_rebuild_theme_data() on its next
-  // invocation. When enabling a module that implements hook_system_info_alter()
-  // to inject a new (testing) theme or manipulate an existing theme, then that
-  // will cause system_list_reset() to be called, but theme data is not
-  // necessarily rebuilt afterwards.
-  // @todo Obsolete with proper installation status for themes.
-  \Drupal::state()->delete('system.theme.data');
+  // Rebuild theme data to update theme states.
+  // When enabling a module that implements hook_system_info_alter() to inject a
+  // new (testing) theme or manipulate an existing theme, then that will cause
+  // system_list_reset() to be called, but theme data is not necessarily rebuilt
+  // afterwards.
+  system_rebuild_theme_data();
 }
 
 /**
diff --git a/core/includes/theme.maintenance.inc b/core/includes/theme.maintenance.inc
index 96dcd2f..4e8a1e6 100644
--- a/core/includes/theme.maintenance.inc
+++ b/core/includes/theme.maintenance.inc
@@ -19,11 +19,6 @@
 function _drupal_maintenance_theme() {
   global $theme, $theme_key, $conf;
 
-  // If $theme is already set, assume the others are set too, and do nothing.
-  if (isset($theme)) {
-    return;
-  }
-
   require_once DRUPAL_ROOT . '/' . settings()->get('path_inc', 'core/includes/path.inc');
   require_once __DIR__ . '/theme.inc';
   require_once __DIR__ . '/common.inc';
@@ -74,6 +69,9 @@ function _drupal_maintenance_theme() {
   }
 
   $themes = list_themes();
+  if (empty($themes) || !isset($themes[$custom_theme])) {
+    $themes = _system_rebuild_theme_data();
+  }
 
   // list_themes() triggers a drupal_alter() in maintenance mode, but we can't
   // let themes alter the .info.yml data until we know a theme's base themes. So
diff --git a/core/lib/Drupal/Core/Extension/ThemeHandler.php b/core/lib/Drupal/Core/Extension/ThemeHandler.php
index c25dcd9..10ee7f2 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandler.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandler.php
@@ -126,11 +126,56 @@ public function __construct(ConfigFactory $config_factory, ModuleHandlerInterfac
   /**
    * {@inheritdoc}
    */
-  public function enable(array $theme_list) {
+  public function enable(array $theme_list, $enable_dependencies = TRUE) {
+    if ($enable_dependencies) {
+      // Get all theme data so we can find dependencies and sort.
+      $theme_data = $this->rebuildThemeData();
+      // Create an associative array with weights as values.
+      $theme_list = array_flip(array_values($theme_list));
+
+      while (list($theme) = each($theme_list)) {
+        if (!isset($theme_data[$theme])) {
+          // This theme is not found in the filesystem, abort.
+          return FALSE;
+        }
+        if ($theme_data[$theme]->status) {
+          // Skip already enabled themes.
+          unset($theme_list[$theme]);
+          continue;
+        }
+        $theme_list[$theme] = $theme_data[$theme]->sort;
+
+        // Add dependencies to the list, with a placeholder weight.
+        // The new themes will be processed as the while loop continues.
+        foreach (array_keys($theme_data[$theme]->requires) as $dependency) {
+          if (!isset($theme_list[$dependency])) {
+            $theme_list[$dependency] = 0;
+          }
+        }
+
+        if (!$theme_list) {
+          // Nothing to do. All themes already enabled.
+          return TRUE;
+        }
+      }
+
+      // Sort the theme list by pre-calculated weights.
+      arsort($theme_list);
+      $theme_list = array_keys($theme_list);
+    }
+
     $this->clearCssCache();
+    $themes_installed = array();
+    $themes_enabled = array();
     $theme_config = $this->configFactory->get('system.theme');
     $disabled_themes = $this->configFactory->get('system.theme.disabled');
     foreach ($theme_list as $key) {
+      // Only process themes that are not already enabled.
+      $enabled = $theme_config->get("enabled.$key") !== NULL;
+      if ($enabled) {
+        continue;
+      }
+
       // Throw an exception if the theme name is too long.
       if (strlen($key) > DRUPAL_EXTENSION_NAME_MAX_LENGTH) {
         throw new ExtensionNameLengthException(String::format('Theme name %name is over the maximum allowed length of @max characters.', array(
@@ -140,20 +185,66 @@ public function enable(array $theme_list) {
       }
 
       // The value is not used; the weight is ignored for themes currently.
-      $theme_config->set("enabled.$key", 0)->save();
-      $disabled_themes->clear($key)->save();
+      $theme_config
+        ->set("enabled.$key", 0)
+        ->save();
+      $disabled_themes
+        ->clear($key)
+        ->save();
 
       // Refresh the theme list as installation of default configuration needs
       // an updated list to work.
       $this->reset();
       // Install default configuration of the theme.
       $this->configInstaller->installDefaultConfig('theme', $key);
+      $this->configInstallDefaultConfig($key);
+
+       // Allow modules to react prior to the installation of a theme.
+      $this->moduleHandler->invokeAll('themes_preinstall', array($key));
+      // Now install the theme if necessary.
+      if (drupal_get_installed_schema_version($key, TRUE) == SCHEMA_UNINSTALLED) {
+        $version = SCHEMA_INSTALLED;
+
+        // Install default configuration of the theme.
+        config_install_default_config('theme', $key);
+
+        drupal_set_installed_schema_version($key, $version);
+        // Allow the theme to perform install tasks.
+        $function = $key . '_install';
+        if (function_exists($function)) {
+          $function();
+        }
+        // Record the fact that it was installed.
+        $themes_installed[] = $key;
+        watchdog('system', '%theme theme installed.', array('%theme' => $key), WATCHDOG_INFO);
+      }
+
+      // Allow modules to react prior to the enabling of a theme.
+      $this->moduleHandler->invokeAll('themes_preenable', array($key));
+
+      // Enable the theme.
+      $function = $key . '_enable';
+      if (function_exists($function)) {
+        $function();
+      }
+
+      // Record the fact that it was enabled.
+      $themes_enabled[] = $key;
+      watchdog('system', '%theme theme enabled.', array('%theme' => $key), WATCHDOG_INFO);
     }
 
     $this->resetSystem();
 
-    // Invoke hook_themes_enabled() after the themes have been enabled.
-    $this->moduleHandler->invokeAll('themes_enabled', array($theme_list));
+    // If any themes were newly installed, invoke hook_themes_installed().
+    if (!empty($themes_installed)) {
+      $this->moduleHandler->invokeAll('themes_installed', $themes_installed);
+    }
+
+    // If any themes were newly enabled, invoke hook_themes_enabled().
+    if (!empty($themes_enabled)) {
+      $this->moduleHandler->invokeAll('themes_enabled', array($themes_enabled));
+    }
+    return TRUE;
   }
 
   /**
@@ -307,6 +398,9 @@ public function rebuildThemeData() {
 
       if (!empty($themes[$key]->info['base theme'])) {
         $sub_themes[] = $key;
+        // Add the defined base theme as dependency to the theme, in order to
+        // re-use the dependency graph resolution of _module_build_dependencies().
+        $themes[$key]->info['dependencies'][] = $themes[$key]->info['base theme'];
       }
 
       $engine = $themes[$key]->info['engine'];
diff --git a/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php b/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
index eef3381..98b4139 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
@@ -17,11 +17,22 @@
    *
    * @param array $theme_list
    *   An array of theme names.
+   * @param bool $enable_dependencies
+   *   If TRUE, dependencies will automatically be added and enabled in the
+   *   correct order. This incurs a significant performance cost, so use FALSE
+   *   if you know $theme_list is already complete and in the correct order.
    *
    * @throws \Drupal\Core\Extension\ExtensionNameLengthException
    *   Thrown when the theme name is to long
+   *
+   * @todo D8: This is almost identical to module_enable() now. Only differences:
+   *   - There is no required default .theme PHP file to load.
+   *   - There is no schema to install.
+   *   - System list, state, theme list, and static resets slightly differ.
+   * @todo hook_themes_installed(), hook_themes_enabled(), etc are not invoked in
+   *   themes, since they are excluded from the hook system.
    */
-  public function enable(array $theme_list);
+  public function enable(array $theme_list, $enable_dependencies = TRUE);
 
   /**
    * Disables a given list of themes.
diff --git a/core/lib/Drupal/Core/Theme/ThemeAccessCheck.php b/core/lib/Drupal/Core/Theme/ThemeAccessCheck.php
index 75afddc..06376fd 100644
--- a/core/lib/Drupal/Core/Theme/ThemeAccessCheck.php
+++ b/core/lib/Drupal/Core/Theme/ThemeAccessCheck.php
@@ -35,7 +35,7 @@ public function access(Route $route, Request $request, AccountInterface $account
    */
   public function checkAccess($theme) {
     $themes = list_themes();
-    return !empty($themes[$theme]->status);
+    return isset($themes[$theme]) && !empty($themes[$theme]->status);
   }
 
 }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
index d553440..181f5b9 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
@@ -37,9 +37,9 @@ function testAdminTheme() {
     $admin_user = $this->drupalCreateUser(array('administer blocks', 'administer themes'));
     $this->drupalLogin($admin_user);
 
-    // Ensure that access to block admin page is denied when theme is disabled.
+    // Ensure the block admin page cannot be accessed for a disabled theme.
     $this->drupalGet('admin/structure/block/list/bartik');
-    $this->assertResponse(403);
+    $this->assertResponse(404);
 
     // Enable admin theme and confirm that tab is accessible.
     theme_enable(array('bartik'));
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index 9d17cac..ed8d235 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -795,6 +795,11 @@ protected function setUp() {
       $this->rebuildContainer();
     }
 
+    // Re-initialize the theme to ensure that tests do not see an inconsistent
+    // behavior when calling functions that would initialize the theme if it has
+    // not been initialized yet.
+    drupal_theme_initialize();
+
     // Reset/rebuild all data structures after enabling the modules.
     $this->resetAll();
 
diff --git a/core/modules/system/lib/Drupal/system/Controller/ThemeController.php b/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
index 852d2b6..14e7e34 100644
--- a/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
+++ b/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
@@ -103,12 +103,9 @@ public function enable(Request $request) {
     $theme = $request->get('theme');
 
     if (isset($theme)) {
-      // Get current list of themes.
-      $themes = list_themes(TRUE);
-
-      // Check if the specified theme is one recognized by the system.
-      if (!empty($themes[$theme])) {
+      if (drupal_get_path('theme', $theme)) {
         theme_enable(array($theme));
+        $themes = list_themes();
         drupal_set_message(t('The %theme theme has been enabled.', array('%theme' => $themes[$theme]->info['name'])));
       }
       else {
diff --git a/core/modules/system/lib/Drupal/system/Tests/Batch/PageTest.php b/core/modules/system/lib/Drupal/system/Tests/Batch/PageTest.php
index f268e02..c0824d6 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Batch/PageTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Batch/PageTest.php
@@ -35,10 +35,10 @@ public static function getInfo() {
   function testBatchProgressPageTheme() {
     // Make sure that the page which starts the batch (an administrative page)
     // is using a different theme than would normally be used by the batch API.
+    \Drupal::service('theme_hander')->enable(array('seven', 'bartik'));
     \Drupal::config('system.theme')
       ->set('default', 'bartik')
       ->save();
-    theme_enable(array('seven'));
     \Drupal::config('system.theme')->set('admin', 'seven')->save();
     // Log in as an administrator who can see the administrative theme.
     $admin_user = $this->drupalCreateUser(array('view the administration theme'));
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php b/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
index 554450a..801bc0c 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
@@ -213,7 +213,7 @@ function testAdministrationTheme() {
 
     // Reset to the default theme settings.
     \Drupal::config('system.theme')
-      ->set('default', 'bartik')
+      ->set('default', 'stark')
       ->save();
     $edit = array(
       'admin_theme' => '0',
@@ -222,10 +222,10 @@ function testAdministrationTheme() {
     $this->drupalPostForm('admin/appearance', $edit, t('Save configuration'));
 
     $this->drupalGet('admin');
-    $this->assertRaw('core/themes/bartik', 'Site default theme used on administration page.');
+    $this->assertRaw('core/themes/stark', 'Site default theme used on administration page.');
 
     $this->drupalGet('node/add');
-    $this->assertRaw('core/themes/bartik', 'Site default theme used on the add content page.');
+    $this->assertRaw('core/themes/stark', 'Site default theme used on the add content page.');
   }
 
   /**
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 492dfd6..616f928 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
@@ -202,11 +202,11 @@ function testFunctionOverride() {
    * Test the list_themes() function.
    */
   function testListThemes() {
+    \Drupal::service('theme_handler')->enable(array('test_subtheme'));
     $themes = list_themes();
     // Check if drupal_theme_access() retrieves enabled themes properly from list_themes().
     $this->assertTrue(drupal_theme_access('test_theme'), 'Enabled theme detected');
-    // Check if list_themes() returns disabled themes.
-    $this->assertTrue(array_key_exists('test_basetheme', $themes), 'Disabled theme detected');
+
     // Check for base theme and subtheme lists.
     $base_theme_list = array('test_basetheme' => 'Theme test base theme');
     $sub_theme_list = array('test_subtheme' => 'Theme test subtheme');
@@ -223,6 +223,7 @@ function testListThemes() {
    * Test the theme_get_setting() function.
    */
   function testThemeGetSetting() {
+    theme_enable(array('test_subtheme'));
     $GLOBALS['theme_key'] = 'test_theme';
     $this->assertIdentical(theme_get_setting('theme_test_setting'), 'default value', 'theme_get_setting() uses the default theme automatically.');
     $this->assertNotEqual(theme_get_setting('subtheme_override', 'test_basetheme'), theme_get_setting('subtheme_override', 'test_subtheme'), 'Base theme\'s default settings values can be overridden by subtheme.');
diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 1ad9b4b..7e972c9 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -10,20 +10,198 @@
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 
 /**
+<<<<<<< HEAD
+=======
+ * Menu callback; displays a listing of all themes.
+ *
+ * @deprecated Use \Drupal\system\Controller\SystemController::themesPage()
+ */
+function system_themes_page() {
+  // Get current list of themes.
+  $themes = system_rebuild_theme_data();
+  uasort($themes, 'system_sort_modules_by_info_name');
+
+  $theme_default = \Drupal::config('system.theme')->get('default');
+  $theme_groups = array('enabled' => array(), 'disabled' => array());
+  $admin_theme = \Drupal::config('system.theme')->get('admin');
+  $admin_theme_options = array();
+
+  foreach ($themes as &$theme) {
+    if (!empty($theme->info['hidden'])) {
+      continue;
+    }
+    $theme->is_default = ($theme->name == $theme_default);
+
+    // Identify theme screenshot.
+    $theme->screenshot = NULL;
+    // Create a list which includes the current theme and all its base themes.
+    if (isset($themes[$theme->name]->base_themes)) {
+      $theme_keys = array_keys($themes[$theme->name]->base_themes);
+      $theme_keys[] = $theme->name;
+    }
+    else {
+      $theme_keys = array($theme->name);
+    }
+    // Look for a screenshot in the current theme or in its closest ancestor.
+    foreach (array_reverse($theme_keys) as $theme_key) {
+      if (isset($themes[$theme_key]) && file_exists($themes[$theme_key]->info['screenshot'])) {
+        $theme->screenshot = array(
+          'uri' => $themes[$theme_key]->info['screenshot'],
+          'alt' => t('Screenshot for !theme theme', array('!theme' => $theme->info['name'])),
+          'title' => t('Screenshot for !theme theme', array('!theme' => $theme->info['name'])),
+          'attributes' => array('class' => array('screenshot')),
+        );
+        break;
+      }
+    }
+
+    if (empty($theme->status)) {
+     // Ensure this theme is compatible with this version of core.
+     // Require the 'content' region to make sure the main page
+     // content has a common place in all themes.
+      $theme->incompatible_core = !isset($theme->info['core']) || ($theme->info['core'] != \Drupal::CORE_COMPATIBILITY) || (!isset($theme->info['regions']['content']));
+      $theme->incompatible_php = version_compare(phpversion(), $theme->info['php']) < 0;
+      // Confirmed that the base theme is available.
+      $theme->incompatible_base = (isset($theme->info['base theme']) && !isset($themes[$theme->info['base theme']]));
+      // Confirm that the theme engine is available.
+      $theme->incompatible_engine = (isset($theme->info['engine']) && !isset($theme->owner));
+    }
+    $theme->operations = array();
+    if (!empty($theme->status) || !$theme->incompatible_core && !$theme->incompatible_php && !$theme->incompatible_base && !$theme->incompatible_engine) {
+      // Create the operations links.
+      $query['theme'] = $theme->name;
+      if (drupal_theme_access($theme)) {
+        $theme->operations[] = array(
+          'title' => t('Settings'),
+          'href' => 'admin/appearance/settings/' . $theme->name,
+          'attributes' => array('title' => t('Settings for !theme theme', array('!theme' => $theme->info['name']))),
+        );
+      }
+      if (!empty($theme->status)) {
+        if (!$theme->is_default) {
+          if ($theme->name != $admin_theme) {
+            $theme->operations[] = array(
+              'title' => t('Disable'),
+              'route_name' => 'system.theme_disable',
+              'query' => $query,
+              'attributes' => array('title' => t('Disable !theme theme', array('!theme' => $theme->info['name']))),
+            );
+          }
+          $theme->operations[] = array(
+            'title' => t('Set default'),
+            'route_name' => 'system.theme_set_default',
+            'query' => $query,
+            'attributes' => array('title' => t('Set !theme as default theme', array('!theme' => $theme->info['name']))),
+          );
+        }
+        $admin_theme_options[$theme->name] = $theme->info['name'];
+      }
+      else {
+        $theme->operations[] = array(
+          'title' => t('Enable'),
+          'route_name' => 'system.theme_enable',
+          'query' => $query,
+          'attributes' => array('title' => t('Enable !theme theme', array('!theme' => $theme->info['name']))),
+        );
+        $theme->operations[] = array(
+          'title' => t('Enable and set default'),
+          'route_name' => 'system.theme_set_default',
+          'query' => $query,
+          'attributes' => array('title' => t('Enable !theme as default theme', array('!theme' => $theme->info['name']))),
+        );
+      }
+    }
+
+    // Add notes to default and administration theme.
+    $theme->notes = array();
+    $theme->classes = array();
+    if ($theme->is_default) {
+      $theme->classes[] = 'theme-default';
+      $theme->notes[] = t('default theme');
+    }
+    if ($theme->name == $admin_theme || ($theme->is_default && $admin_theme == '0')) {
+      $theme->classes[] = 'theme-admin';
+      $theme->notes[] = t('admin theme');
+    }
+
+    // Sort enabled and disabled themes into their own groups.
+    $theme_groups[$theme->status ? 'enabled' : 'disabled'][] = $theme;
+  }
+
+  // There are two possible theme groups.
+  $theme_group_titles = array(
+    'enabled' => format_plural(count($theme_groups['enabled']), 'Enabled theme', 'Enabled themes'),
+  );
+  if (!empty($theme_groups['disabled'])) {
+    $theme_group_titles['disabled'] = format_plural(count($theme_groups['disabled']), 'Disabled theme', 'Disabled themes');
+  }
+
+  uasort($theme_groups['enabled'], 'system_sort_themes');
+  drupal_alter('system_themes_page', $theme_groups);
+
+  $build = array(
+    '#sorted' => TRUE,
+  );
+  $build['system_themes_page'] = array(
+    '#theme' => 'system_themes_page',
+    '#theme_groups' => $theme_groups,
+    '#theme_group_titles' => $theme_group_titles,
+  );
+  $build['admin_form'] = drupal_get_form('system_themes_admin_form', $admin_theme_options);
+  return $build;
+}
+
+/**
+ * Form to select the administration theme.
+ *
+ * @ingroup forms
+ * @see system_themes_admin_form_submit()
+ */
+function system_themes_admin_form($form, &$form_state, $theme_options) {
+  // Administration theme settings.
+  $form['admin_theme'] = array(
+    '#type' => 'details',
+    '#title' => t('Administration theme'),
+  );
+  $form['admin_theme']['admin_theme'] = array(
+    '#type' => 'select',
+    '#options' => array(0 => t('Default theme')) + $theme_options,
+    '#title' => t('Administration theme'),
+    '#description' => t('Choose "Default theme" to always use the same theme as the rest of the site.'),
+    '#default_value' => \Drupal::config('system.theme')->get('admin'),
+  );
+  $form['admin_theme']['actions'] = array('#type' => 'actions');
+  $form['admin_theme']['actions']['submit'] = array(
+    '#type' => 'submit',
+    '#value' => t('Save configuration'),
+  );
+  return $form;
+}
+
+/**
+ * Process system_themes_admin_form form submissions.
+ */
+function system_themes_admin_form_submit($form, &$form_state) {
+  drupal_set_message(t('The configuration options have been saved.'));
+  \Drupal::config('system.theme')->set('admin', $form_state['values']['admin_theme'])->save();
+}
+
+/**
+>>>>>>> Applying patch from issue 1067408 comment 117
  * Menu callback; Set the default theme.
  */
 function system_theme_default() {
   $request = \Drupal::request();
   $theme = $request->get('theme');
   if (!empty($theme)) {
-    // Get current list of themes.
-    $themes = list_themes();
 
     // Check if the specified theme is one recognized by the system.
-    if (!empty($themes[$theme])) {
+    if (drupal_get_path('theme', $theme)) {
+      $themes = list_themes();
       // Enable the theme if it is currently disabled.
-      if (empty($themes[$theme]->status)) {
-       theme_enable(array($theme));
+      if (!isset($themes[$theme])) {
+        \Drupal::service('theme_handler')->enable(array($theme));
+        $themes = list_themes();
       }
       // Set the default theme.
       \Drupal::config('system.theme')
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index c2cf620..d441753 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -2335,6 +2335,7 @@ function system_get_info($type, $name = NULL) {
     }
   }
   else {
+    // @todo Migrate theme info to ModuleInfo implementation.
     $list = system_list($type);
     foreach ($list as $shortname => $item) {
       if (!empty($item->status)) {
@@ -2360,6 +2361,8 @@ function system_get_info($type, $name = NULL) {
  *   returned.
  *
  * @see \Drupal\Core\Utility\ModuleInfo
+ *
+ * @todo Merge this helper entirely into system_get_info()?
  */
 function system_get_module_info($property) {
   static $info;
@@ -2499,29 +2502,29 @@ function _system_rebuild_theme_data() {
  *   Array of all available themes and their data.
  */
 function system_rebuild_theme_data() {
-  $themes = _system_rebuild_theme_data();
+  $files = array();
+  $themes = \Drupal::service('theme_handler')->rebuildThemeData();
   ksort($themes);
-  // @todo This function has no business in determining/setting the status of
-  //   a theme, but various other functions expect it to return themes with a
-  //   $status property. system_list() stores the return value of this function
-  //   in state, and ensures to set/override the $status property for each theme
-  //   based on the current config. Remove this code when themes have a proper
-  //   installation status.
-  // @see http://drupal.org/node/1067408
+
+  // Add name, status, and schema version.
   $enabled_themes = (array) \Drupal::config('system.theme')->get('enabled');
-  $files = array();
+  $disabled_themes = (array) \Drupal::config('system.theme.disabled')->get();
+  $all_themes = $enabled_themes + $disabled_themes;
   foreach ($themes as $name => $theme) {
+    $theme->name = $name;
+    $theme->weight = isset($all_themes[$name]) ? $all_themes[$name] : 0;
     $theme->status = (int) isset($enabled_themes[$name]);
+    $theme->schema_version = SCHEMA_UNINSTALLED;
     $files[$name] = $theme->filename;
+
+    // Replace last known theme data state.
+    \Drupal::state()->set('system.theme.data.' . $name, $theme);
   }
-  // Replace last known theme data state.
-  // @todo Obsolete with proper installation status for themes.
-  \Drupal::state()->set('system.theme.data', $themes);
+  $themes = \Drupal::moduleHandler()->buildModuleDependencies($themes);
 
   // 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;
 }
 
@@ -2545,25 +2548,26 @@ function _system_default_theme_features() {
 /**
  * Get a list of available regions from a specified theme.
  *
- * @param $theme_key
- *   The name of a theme.
+ * @param $theme
+ *   A theme object, or the name of a theme.
  * @param $show
  *   Possible values: REGIONS_ALL or REGIONS_VISIBLE. Visible excludes hidden
  *   regions.
  * @return
  *   An array of regions in the form $region['name'] = 'description'.
  */
-function system_region_list($theme_key, $show = REGIONS_ALL) {
-  $themes = list_themes();
-  if (!isset($themes[$theme_key])) {
-    return array();
+function system_region_list($theme, $show = REGIONS_ALL) {
+  if (!is_object($theme)) {
+    $themes = list_themes();
+    if (!isset($themes[$theme])) {
+      return array();
+    }
+    $theme = $themes[$theme];
   }
-
   $list = array();
-  $info = $themes[$theme_key]->info;
   // If requested, suppress hidden regions. See block_admin_display_form().
-  foreach ($info['regions'] as $name => $label) {
-    if ($show == REGIONS_ALL || !isset($info['regions_hidden']) || !in_array($name, $info['regions_hidden'])) {
+  foreach ($theme->info['regions'] as $name => $label) {
+    if ($show == REGIONS_ALL || !isset($theme->info['regions_hidden']) || !in_array($name, $theme->info['regions_hidden'])) {
       $list[$name] = t($label);
     }
   }
diff --git a/theme-1067408.patch b/theme-1067408.patch
new file mode 100644
index 0000000..448dd4e
--- /dev/null
+++ b/theme-1067408.patch
@@ -0,0 +1,541 @@
+diff --git a/core/includes/module.inc b/core/includes/module.inc
+index 429f5db..b45f447 100644
+--- a/core/includes/module.inc
++++ b/core/includes/module.inc
+@@ -11,7 +11,7 @@
+  *
+  * @param $type
+  *   The type of list to return:
+- *   - module_enabled: All enabled modules.
++ *   - module: All enabled modules.
+  *   - bootstrap: All enabled modules required for bootstrap.
+  *   - theme: All themes.
+  *
+@@ -40,30 +40,26 @@ function system_list($type) {
+     );
+     // Build a list of themes.
+     $enabled_themes = (array) \Drupal::config('system.theme')->get('enabled');
+-    // @todo Themes include all themes, including disabled/uninstalled. This
+-    //   system.theme.data state will go away entirely as soon as themes have
+-    //   a proper installation status.
+-    // @see http://drupal.org/node/1067408
+-    $theme_data = \Drupal::state()->get('system.theme.data');
+-    if (empty($theme_data)) {
+-      // @todo: system_list() may be called from _drupal_bootstrap_code(), in
++    array_walk($enabled_themes, function (&$value, $key) {
++      $value = 'system.theme.data.' . $key;
++    });
++    $theme_data = (array) \Drupal::state()->getMultiple($enabled_themes);
++    // @todo Remove me?
++    if (0 && empty($theme_data)) {
++      // system_list() may be called from _drupal_bootstrap_code() and
+       // which case system.module is not loaded yet.
+       // Prevent a filesystem scan in drupal_load() and include it directly.
+-      // @see http://drupal.org/node/1067408
+       require_once DRUPAL_ROOT . '/core/modules/system/system.module';
+       $theme_data = system_rebuild_theme_data();
+     }
+     foreach ($theme_data as $name => $theme) {
+-      $theme->status = (int) isset($enabled_themes[$name]);
+       $lists['theme'][$name] = $theme;
+       // Build a list of filenames so drupal_get_filename can use it.
+-      if (isset($enabled_themes[$name])) {
+-        $lists['filepaths'][] = array(
+-          'type' => 'theme',
+-          'name' => $name,
+-          'filepath' => $theme->filename,
+-        );
+-      }
++      $lists['filepaths'][] = array(
++        'type' => 'theme',
++        'name' => $name,
++        'filepath' => $theme->filename,
++      );
+     }
+     // @todo Move into list_themes(). Read info for a particular requested
+     //   theme from state instead.
+@@ -112,14 +108,12 @@ function system_list_reset() {
+   drupal_static_reset('list_themes');
+   cache('bootstrap')->delete('system_list');
+   cache()->delete('system_info');
+-  // Remove last known theme data state.
+-  // This causes system_list() to call system_rebuild_theme_data() on its next
+-  // invocation. When enabling a module that implements hook_system_info_alter()
+-  // to inject a new (testing) theme or manipulate an existing theme, then that
+-  // will cause system_list_reset() to be called, but theme data is not
+-  // necessarily rebuilt afterwards.
+-  // @todo Obsolete with proper installation status for themes.
+-  \Drupal::state()->delete('system.theme.data');
++  // Rebuild theme data to update theme states.
++  // When enabling a module that implements hook_system_info_alter() to inject a
++  // new (testing) theme or manipulate an existing theme, then that will cause
++  // system_list_reset() to be called, but theme data is not necessarily rebuilt
++  // afterwards.
++  system_rebuild_theme_data();
+ }
+ 
+ /**
+diff --git a/core/includes/theme.maintenance.inc b/core/includes/theme.maintenance.inc
+index 96dcd2f..4e8a1e6 100644
+--- a/core/includes/theme.maintenance.inc
++++ b/core/includes/theme.maintenance.inc
+@@ -19,11 +19,6 @@
+ function _drupal_maintenance_theme() {
+   global $theme, $theme_key, $conf;
+ 
+-  // If $theme is already set, assume the others are set too, and do nothing.
+-  if (isset($theme)) {
+-    return;
+-  }
+-
+   require_once DRUPAL_ROOT . '/' . settings()->get('path_inc', 'core/includes/path.inc');
+   require_once __DIR__ . '/theme.inc';
+   require_once __DIR__ . '/common.inc';
+@@ -74,6 +69,9 @@ function _drupal_maintenance_theme() {
+   }
+ 
+   $themes = list_themes();
++  if (empty($themes) || !isset($themes[$custom_theme])) {
++    $themes = _system_rebuild_theme_data();
++  }
+ 
+   // list_themes() triggers a drupal_alter() in maintenance mode, but we can't
+   // let themes alter the .info.yml data until we know a theme's base themes. So
+diff --git a/core/lib/Drupal/Core/Extension/ThemeHandler.php b/core/lib/Drupal/Core/Extension/ThemeHandler.php
+index 40e59cb..ce69ab6 100644
+--- a/core/lib/Drupal/Core/Extension/ThemeHandler.php
++++ b/core/lib/Drupal/Core/Extension/ThemeHandler.php
+@@ -112,11 +112,56 @@ public function __construct(ConfigFactory $config_factory, ModuleHandlerInterfac
+   /**
+    * {@inheritdoc}
+    */
+-  public function enable(array $theme_list) {
++  public function enable(array $theme_list, $enable_dependencies = TRUE) {
++    if ($enable_dependencies) {
++      // Get all theme data so we can find dependencies and sort.
++      $theme_data = $this->rebuildThemeData();
++      // Create an associative array with weights as values.
++      $theme_list = array_flip(array_values($theme_list));
++
++      while (list($theme) = each($theme_list)) {
++        if (!isset($theme_data[$theme])) {
++          // This theme is not found in the filesystem, abort.
++          return FALSE;
++        }
++        if ($theme_data[$theme]->status) {
++          // Skip already enabled themes.
++          unset($theme_list[$theme]);
++          continue;
++        }
++        $theme_list[$theme] = $theme_data[$theme]->sort;
++
++        // Add dependencies to the list, with a placeholder weight.
++        // The new themes will be processed as the while loop continues.
++        foreach (array_keys($theme_data[$theme]->requires) as $dependency) {
++          if (!isset($theme_list[$dependency])) {
++            $theme_list[$dependency] = 0;
++          }
++        }
++
++        if (!$theme_list) {
++          // Nothing to do. All themes already enabled.
++          return TRUE;
++        }
++      }
++
++      // Sort the theme list by pre-calculated weights.
++      arsort($theme_list);
++      $theme_list = array_keys($theme_list);
++    }
++
+     $this->clearCssCache();
++    $themes_installed = array();
++    $themes_enabled = array();
+     $theme_config = $this->configFactory->get('system.theme');
+     $disabled_themes = $this->configFactory->get('system.theme.disabled');
+     foreach ($theme_list as $key) {
++      // Only process themes that are not already enabled.
++      $enabled = $theme_config->get("enabled.$key") !== NULL;
++      if ($enabled) {
++        continue;
++      }
++
+       // Throw an exception if the theme name is too long.
+       if (strlen($key) > DRUPAL_EXTENSION_NAME_MAX_LENGTH) {
+         throw new ExtensionNameLengthException(String::format('Theme name %name is over the maximum allowed length of @max characters.', array(
+@@ -126,20 +171,65 @@ public function enable(array $theme_list) {
+       }
+ 
+       // The value is not used; the weight is ignored for themes currently.
+-      $theme_config->set("enabled.$key", 0)->save();
+-      $disabled_themes->clear($key)->save();
++      $theme_config
++        ->set("enabled.$key", 0)
++        ->save();
++      $disabled_themes
++        ->clear($key)
++        ->save();
+ 
+       // Refresh the theme list as config_install_default_config() needs an
+       // updated list to work.
+       $this->reset();
+       // Install default configuration of the theme.
+       $this->configInstallDefaultConfig($key);
++
++       // Allow modules to react prior to the installation of a theme.
++      $this->moduleHandler->invokeAll('themes_preinstall', array($key));
++      // Now install the theme if necessary.
++      if (drupal_get_installed_schema_version($key, TRUE) == SCHEMA_UNINSTALLED) {
++        $version = SCHEMA_INSTALLED;
++
++        // Install default configuration of the theme.
++        config_install_default_config('theme', $key);
++
++        drupal_set_installed_schema_version($key, $version);
++        // Allow the theme to perform install tasks.
++        $function = $key . '_install';
++        if (function_exists($function)) {
++          $function();
++        }
++        // Record the fact that it was installed.
++        $themes_installed[] = $key;
++        watchdog('system', '%theme theme installed.', array('%theme' => $key), WATCHDOG_INFO);
++      }
++
++      // Allow modules to react prior to the enabling of a theme.
++      $this->moduleHandler->invokeAll('themes_preenable', array($key));
++
++      // Enable the theme.
++      $function = $key . '_enable';
++      if (function_exists($function)) {
++        $function();
++      }
++
++      // Record the fact that it was enabled.
++      $themes_enabled[] = $key;
++      watchdog('system', '%theme theme enabled.', array('%theme' => $key), WATCHDOG_INFO);
+     }
+ 
+     $this->resetSystem();
+ 
+-    // Invoke hook_themes_enabled() after the themes have been enabled.
+-    $this->moduleHandler->invokeAll('themes_enabled', array($theme_list));
++    // If any themes were newly installed, invoke hook_themes_installed().
++    if (!empty($themes_installed)) {
++      $this->moduleHandler->invokeAll('themes_installed', $themes_installed);
++    }
++
++    // If any themes were newly enabled, invoke hook_themes_enabled().
++    if (!empty($themes_enabled)) {
++      $this->moduleHandler->invokeAll('themes_enabled', array($themes_enabled));
++    }
++    return TRUE;
+   }
+ 
+   /**
+@@ -293,6 +383,9 @@ public function rebuildThemeData() {
+ 
+       if (!empty($themes[$key]->info['base theme'])) {
+         $sub_themes[] = $key;
++        // Add the defined base theme as dependency to the theme, in order to
++        // re-use the dependency graph resolution of _module_build_dependencies().
++        $themes[$key]->info['dependencies'][] = $themes[$key]->info['base theme'];
+       }
+ 
+       $engine = $themes[$key]->info['engine'];
+diff --git a/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php b/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
+index eef3381..98b4139 100644
+--- a/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
++++ b/core/lib/Drupal/Core/Extension/ThemeHandlerInterface.php
+@@ -17,11 +17,22 @@
+    *
+    * @param array $theme_list
+    *   An array of theme names.
++   * @param bool $enable_dependencies
++   *   If TRUE, dependencies will automatically be added and enabled in the
++   *   correct order. This incurs a significant performance cost, so use FALSE
++   *   if you know $theme_list is already complete and in the correct order.
+    *
+    * @throws \Drupal\Core\Extension\ExtensionNameLengthException
+    *   Thrown when the theme name is to long
++   *
++   * @todo D8: This is almost identical to module_enable() now. Only differences:
++   *   - There is no required default .theme PHP file to load.
++   *   - There is no schema to install.
++   *   - System list, state, theme list, and static resets slightly differ.
++   * @todo hook_themes_installed(), hook_themes_enabled(), etc are not invoked in
++   *   themes, since they are excluded from the hook system.
+    */
+-  public function enable(array $theme_list);
++  public function enable(array $theme_list, $enable_dependencies = TRUE);
+ 
+   /**
+    * Disables a given list of themes.
+diff --git a/core/lib/Drupal/Core/Theme/ThemeAccessCheck.php b/core/lib/Drupal/Core/Theme/ThemeAccessCheck.php
+index 75afddc..06376fd 100644
+--- a/core/lib/Drupal/Core/Theme/ThemeAccessCheck.php
++++ b/core/lib/Drupal/Core/Theme/ThemeAccessCheck.php
+@@ -35,7 +35,7 @@ public function access(Route $route, Request $request, AccountInterface $account
+    */
+   public function checkAccess($theme) {
+     $themes = list_themes();
+-    return !empty($themes[$theme]->status);
++    return isset($themes[$theme]) && !empty($themes[$theme]->status);
+   }
+ 
+ }
+diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
+index d553440..181f5b9 100644
+--- a/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
++++ b/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
+@@ -37,9 +37,9 @@ function testAdminTheme() {
+     $admin_user = $this->drupalCreateUser(array('administer blocks', 'administer themes'));
+     $this->drupalLogin($admin_user);
+ 
+-    // Ensure that access to block admin page is denied when theme is disabled.
++    // Ensure the block admin page cannot be accessed for a disabled theme.
+     $this->drupalGet('admin/structure/block/list/bartik');
+-    $this->assertResponse(403);
++    $this->assertResponse(404);
+ 
+     // Enable admin theme and confirm that tab is accessible.
+     theme_enable(array('bartik'));
+diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+index 265012e..2ee1d39 100644
+--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
++++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+@@ -830,6 +830,11 @@ protected function setUp() {
+       $this->rebuildContainer();
+     }
+ 
++    // Re-initialize the theme to ensure that tests do not see an inconsistent
++    // behavior when calling functions that would initialize the theme if it has
++    // not been initialized yet.
++    drupal_theme_initialize();
++
+     // Reset/rebuild all data structures after enabling the modules.
+     $this->resetAll();
+ 
+diff --git a/core/modules/system/lib/Drupal/system/Controller/ThemeController.php b/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
+index 852d2b6..14e7e34 100644
+--- a/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
++++ b/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
+@@ -103,12 +103,9 @@ public function enable(Request $request) {
+     $theme = $request->get('theme');
+ 
+     if (isset($theme)) {
+-      // Get current list of themes.
+-      $themes = list_themes(TRUE);
+-
+-      // Check if the specified theme is one recognized by the system.
+-      if (!empty($themes[$theme])) {
++      if (drupal_get_path('theme', $theme)) {
+         theme_enable(array($theme));
++        $themes = list_themes();
+         drupal_set_message(t('The %theme theme has been enabled.', array('%theme' => $themes[$theme]->info['name'])));
+       }
+       else {
+diff --git a/core/modules/system/lib/Drupal/system/Tests/Batch/PageTest.php b/core/modules/system/lib/Drupal/system/Tests/Batch/PageTest.php
+index f268e02..c0824d6 100644
+--- a/core/modules/system/lib/Drupal/system/Tests/Batch/PageTest.php
++++ b/core/modules/system/lib/Drupal/system/Tests/Batch/PageTest.php
+@@ -35,10 +35,10 @@ public static function getInfo() {
+   function testBatchProgressPageTheme() {
+     // Make sure that the page which starts the batch (an administrative page)
+     // is using a different theme than would normally be used by the batch API.
++    \Drupal::service('theme_hander')->enable(array('seven', 'bartik'));
+     \Drupal::config('system.theme')
+       ->set('default', 'bartik')
+       ->save();
+-    theme_enable(array('seven'));
+     \Drupal::config('system.theme')->set('admin', 'seven')->save();
+     // Log in as an administrator who can see the administrative theme.
+     $admin_user = $this->drupalCreateUser(array('view the administration theme'));
+diff --git a/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php b/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
+index 554450a..801bc0c 100644
+--- a/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
++++ b/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
+@@ -213,7 +213,7 @@ function testAdministrationTheme() {
+ 
+     // Reset to the default theme settings.
+     \Drupal::config('system.theme')
+-      ->set('default', 'bartik')
++      ->set('default', 'stark')
+       ->save();
+     $edit = array(
+       'admin_theme' => '0',
+@@ -222,10 +222,10 @@ function testAdministrationTheme() {
+     $this->drupalPostForm('admin/appearance', $edit, t('Save configuration'));
+ 
+     $this->drupalGet('admin');
+-    $this->assertRaw('core/themes/bartik', 'Site default theme used on administration page.');
++    $this->assertRaw('core/themes/stark', 'Site default theme used on administration page.');
+ 
+     $this->drupalGet('node/add');
+-    $this->assertRaw('core/themes/bartik', 'Site default theme used on the add content page.');
++    $this->assertRaw('core/themes/stark', 'Site default theme used on the add content page.');
+   }
+ 
+   /**
+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 492dfd6..616f928 100644
+--- a/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
++++ b/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
+@@ -202,11 +202,11 @@ function testFunctionOverride() {
+    * Test the list_themes() function.
+    */
+   function testListThemes() {
++    \Drupal::service('theme_handler')->enable(array('test_subtheme'));
+     $themes = list_themes();
+     // Check if drupal_theme_access() retrieves enabled themes properly from list_themes().
+     $this->assertTrue(drupal_theme_access('test_theme'), 'Enabled theme detected');
+-    // Check if list_themes() returns disabled themes.
+-    $this->assertTrue(array_key_exists('test_basetheme', $themes), 'Disabled theme detected');
++
+     // Check for base theme and subtheme lists.
+     $base_theme_list = array('test_basetheme' => 'Theme test base theme');
+     $sub_theme_list = array('test_subtheme' => 'Theme test subtheme');
+@@ -223,6 +223,7 @@ function testListThemes() {
+    * Test the theme_get_setting() function.
+    */
+   function testThemeGetSetting() {
++    theme_enable(array('test_subtheme'));
+     $GLOBALS['theme_key'] = 'test_theme';
+     $this->assertIdentical(theme_get_setting('theme_test_setting'), 'default value', 'theme_get_setting() uses the default theme automatically.');
+     $this->assertNotEqual(theme_get_setting('subtheme_override', 'test_basetheme'), theme_get_setting('subtheme_override', 'test_subtheme'), 'Base theme\'s default settings values can be overridden by subtheme.');
+diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
+index 3af30c8..c59ad87 100644
+--- a/core/modules/system/system.admin.inc
++++ b/core/modules/system/system.admin.inc
+@@ -21,8 +21,9 @@ function system_themes_page() {
+   uasort($themes, 'system_sort_modules_by_info_name');
+ 
+   $theme_default = \Drupal::config('system.theme')->get('default');
+-  $theme_groups  = array();
++  $theme_groups = array('enabled' => array(), 'disabled' => array());
+   $admin_theme = \Drupal::config('system.theme')->get('admin');
++  $admin_theme_options = array();
+ 
+   foreach ($themes as &$theme) {
+     if (!empty($theme->info['hidden'])) {
+@@ -191,14 +192,14 @@ function system_theme_default() {
+   $request = \Drupal::request();
+   $theme = $request->get('theme');
+   if (!empty($theme)) {
+-    // Get current list of themes.
+-    $themes = list_themes();
+ 
+     // Check if the specified theme is one recognized by the system.
+-    if (!empty($themes[$theme])) {
++    if (drupal_get_path('theme', $theme)) {
++      $themes = list_themes();
+       // Enable the theme if it is currently disabled.
+-      if (empty($themes[$theme]->status)) {
+-       theme_enable(array($theme));
++      if (!isset($themes[$theme])) {
++        \Drupal::service('theme_handler')->enable(array($theme));
++        $themes = list_themes();
+       }
+       // Set the default theme.
+       \Drupal::config('system.theme')
+diff --git a/core/modules/system/system.module b/core/modules/system/system.module
+index fac4c21..426b4f3 100644
+--- a/core/modules/system/system.module
++++ b/core/modules/system/system.module
+@@ -2308,6 +2308,7 @@ function system_get_info($type, $name = NULL) {
+     }
+   }
+   else {
++    // @todo Migrate theme info to ModuleInfo implementation.
+     $list = system_list($type);
+     foreach ($list as $shortname => $item) {
+       if (!empty($item->status)) {
+@@ -2333,6 +2334,8 @@ function system_get_info($type, $name = NULL) {
+  *   returned.
+  *
+  * @see \Drupal\Core\Utility\ModuleInfo
++ *
++ * @todo Merge this helper entirely into system_get_info()?
+  */
+ function system_get_module_info($property) {
+   static $info;
+@@ -2472,29 +2475,29 @@ function _system_rebuild_theme_data() {
+  *   Array of all available themes and their data.
+  */
+ function system_rebuild_theme_data() {
+-  $themes = _system_rebuild_theme_data();
++  $files = array();
++  $themes = \Drupal::service('theme_handler')->rebuildThemeData();
+   ksort($themes);
+-  // @todo This function has no business in determining/setting the status of
+-  //   a theme, but various other functions expect it to return themes with a
+-  //   $status property. system_list() stores the return value of this function
+-  //   in state, and ensures to set/override the $status property for each theme
+-  //   based on the current config. Remove this code when themes have a proper
+-  //   installation status.
+-  // @see http://drupal.org/node/1067408
++
++  // Add name, status, and schema version.
+   $enabled_themes = (array) \Drupal::config('system.theme')->get('enabled');
+-  $files = array();
++  $disabled_themes = (array) \Drupal::config('system.theme.disabled')->get();
++  $all_themes = $enabled_themes + $disabled_themes;
+   foreach ($themes as $name => $theme) {
++    $theme->name = $name;
++    $theme->weight = isset($all_themes[$name]) ? $all_themes[$name] : 0;
+     $theme->status = (int) isset($enabled_themes[$name]);
++    $theme->schema_version = SCHEMA_UNINSTALLED;
+     $files[$name] = $theme->filename;
++
++    // Replace last known theme data state.
++    \Drupal::state()->set('system.theme.data.' . $name, $theme);
+   }
+-  // Replace last known theme data state.
+-  // @todo Obsolete with proper installation status for themes.
+-  \Drupal::state()->set('system.theme.data', $themes);
++  $themes = \Drupal::moduleHandler()->buildModuleDependencies($themes);
+ 
+   // 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;
+ }
+ 
+@@ -2518,25 +2521,26 @@ function _system_default_theme_features() {
+ /**
+  * Get a list of available regions from a specified theme.
+  *
+- * @param $theme_key
+- *   The name of a theme.
++ * @param $theme
++ *   A theme object, or the name of a theme.
+  * @param $show
+  *   Possible values: REGIONS_ALL or REGIONS_VISIBLE. Visible excludes hidden
+  *   regions.
+  * @return
+  *   An array of regions in the form $region['name'] = 'description'.
+  */
+-function system_region_list($theme_key, $show = REGIONS_ALL) {
+-  $themes = list_themes();
+-  if (!isset($themes[$theme_key])) {
+-    return array();
++function system_region_list($theme, $show = REGIONS_ALL) {
++  if (!is_object($theme)) {
++    $themes = list_themes();
++    if (!isset($themes[$theme])) {
++      return array();
++    }
++    $theme = $themes[$theme];
+   }
+-
+   $list = array();
+-  $info = $themes[$theme_key]->info;
+   // If requested, suppress hidden regions. See block_admin_display_form().
+-  foreach ($info['regions'] as $name => $label) {
+-    if ($show == REGIONS_ALL || !isset($info['regions_hidden']) || !in_array($name, $info['regions_hidden'])) {
++  foreach ($theme->info['regions'] as $name => $label) {
++    if ($show == REGIONS_ALL || !isset($theme->info['regions_hidden']) || !in_array($name, $theme->info['regions_hidden'])) {
+       $list[$name] = t($label);
+     }
+   }