diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 5a13735..805457c 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -99,8 +99,8 @@ function drupal_theme_initialize() {
   $themes = list_themes();
 
   // @todo Let the theme.negotiator listen to the kernel request event.
-  $request = Drupal::request();
-  $theme = Drupal::service('theme.negotiator')->determineActiveTheme($request) ?: 'stark';
+  $request = \Drupal::request();
+  $theme = \Drupal::service('theme.negotiator')->determineActiveTheme($request) ?: 'stark';
 
   // Store the identifier for retrieving theme settings with.
   $theme_key = $theme;
@@ -115,7 +115,7 @@ function drupal_theme_initialize() {
   _drupal_theme_initialize($themes[$theme], array_reverse($base_theme));
 
   // Themes can have alter functions, so reset the drupal_alter() cache.
-  Drupal::moduleHandler()->resetImplementations();
+  \Drupal::moduleHandler()->resetImplementations();
 }
 
 /**
diff --git a/core/lib/Drupal/Core/Theme/DefaultNegotiator.php b/core/lib/Drupal/Core/Theme/DefaultNegotiator.php
index f155b0d..d596678 100644
--- a/core/lib/Drupal/Core/Theme/DefaultNegotiator.php
+++ b/core/lib/Drupal/Core/Theme/DefaultNegotiator.php
@@ -16,6 +16,13 @@
 class DefaultNegotiator implements ThemeNegotiatorInterface {
 
   /**
+   * The system theme config object.
+   *
+   * @var \Drupal\Core\Config\Config
+   */
+  protected $config;
+
+  /**
    * Constructs a DefaultNegotiator object.
    *
    * @param \Drupal\Core\Config\ConfigFactory $config_factory
diff --git a/core/modules/block/lib/Drupal/block/Theme/AdminDemoNegotiator.php b/core/modules/block/lib/Drupal/block/Theme/AdminDemoNegotiator.php
index 2d9d351..d3dcb33 100644
--- a/core/modules/block/lib/Drupal/block/Theme/AdminDemoNegotiator.php
+++ b/core/modules/block/lib/Drupal/block/Theme/AdminDemoNegotiator.php
@@ -27,4 +27,4 @@ public function determineActiveTheme(Request $request) {
     }
   }
 
-} 
+}
diff --git a/core/modules/search/lib/Drupal/search/Tests/SearchPageOverrideTest.php b/core/modules/search/lib/Drupal/search/Tests/SearchPageOverrideTest.php
index ab3f913..101b745 100644
--- a/core/modules/search/lib/Drupal/search/Tests/SearchPageOverrideTest.php
+++ b/core/modules/search/lib/Drupal/search/Tests/SearchPageOverrideTest.php
@@ -38,7 +38,7 @@ function setUp() {
 
     // Enable the extra type module for searching.
     \Drupal::config('search.settings')->set('active_plugins', array('node_search', 'user_search', 'search_extra_type_search'))->save();
-    \Drupal::state()->set('menu_rebuild_needed', TRUE);
+    \Drupal::service('router.builder')->rebuild();
   }
 
   function testSearchPageHook() {
diff --git a/core/modules/shortcut/lib/Drupal/shortcut/Tests/ShortcutLinksTest.php b/core/modules/shortcut/lib/Drupal/shortcut/Tests/ShortcutLinksTest.php
index 1fdb3ba..b747d79 100644
--- a/core/modules/shortcut/lib/Drupal/shortcut/Tests/ShortcutLinksTest.php
+++ b/core/modules/shortcut/lib/Drupal/shortcut/Tests/ShortcutLinksTest.php
@@ -145,6 +145,7 @@ function testShortcutLinkDelete() {
    */
   function testNoShortcutLink() {
     // Change to a theme that displays shortcuts.
+    theme_enable(array('seven'));
     \Drupal::config('system.theme')
       ->set('default', 'seven')
       ->save();
@@ -157,8 +158,9 @@ function testNoShortcutLink() {
     $this->assertNoRaw('add-shortcut', 'Add to shortcuts link was not shown on a page the user does not have access to.');
 
     // Verify that the testing mechanism works by verifying the shortcut
-    // link appears on admin/content.
-    $this->drupalGet('admin/content');
+    // link appears on admin/people.
+    $this->drupalGet('admin/people');
     $this->assertRaw('add-shortcut', 'Add to shortcuts link was shown on a page the user does have access to.');
   }
+
 }
diff --git a/core/modules/shortcut/lib/Drupal/shortcut/Tests/ShortcutTestBase.php b/core/modules/shortcut/lib/Drupal/shortcut/Tests/ShortcutTestBase.php
index 06088ef..e0bdb31 100644
--- a/core/modules/shortcut/lib/Drupal/shortcut/Tests/ShortcutTestBase.php
+++ b/core/modules/shortcut/lib/Drupal/shortcut/Tests/ShortcutTestBase.php
@@ -69,7 +69,7 @@ function setUp() {
     }
 
     // Create users.
-    $this->admin_user = $this->drupalCreateUser(array('access toolbar', 'administer shortcuts', 'view the administration theme', 'create article content', 'create page content', 'access content overview'));
+    $this->admin_user = $this->drupalCreateUser(array('access toolbar', 'administer shortcuts', 'view the administration theme', 'create article content', 'create page content', 'access content overview', 'administer users'));
     $this->shortcut_user = $this->drupalCreateUser(array('customize shortcut links', 'switch shortcut sets'));
 
     // Create a node.
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 9a13acb..554450a 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
@@ -178,7 +178,7 @@ function testThemeSettings() {
    * Test the administration theme functionality.
    */
   function testAdministrationTheme() {
-    theme_enable(array('seven'));
+    theme_enable(array('bartik', 'seven'));
 
     // Enable an administration theme and show it on the node admin pages.
     $edit = array(
diff --git a/core/modules/system/lib/Drupal/system/Theme/AdminNegotiator.php b/core/modules/system/lib/Drupal/system/Theme/AdminNegotiator.php
index 2bd4bd5..72359ea 100644
--- a/core/modules/system/lib/Drupal/system/Theme/AdminNegotiator.php
+++ b/core/modules/system/lib/Drupal/system/Theme/AdminNegotiator.php
@@ -68,4 +68,4 @@ public function determineActiveTheme(Request $request) {
     }
   }
 
-} 
+}
diff --git a/core/modules/system/lib/Drupal/system/Theme/BatchNegotiator.php b/core/modules/system/lib/Drupal/system/Theme/BatchNegotiator.php
index e6694e9..a10374d 100644
--- a/core/modules/system/lib/Drupal/system/Theme/BatchNegotiator.php
+++ b/core/modules/system/lib/Drupal/system/Theme/BatchNegotiator.php
@@ -51,4 +51,4 @@ public function determineActiveTheme(Request $request) {
     }
   }
 
-} 
+}
diff --git a/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/EventSubscriber/ActiveTrailSubscriber.php b/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/EventSubscriber/ActiveTrailSubscriber.php
new file mode 100644
index 0000000..4bb3595
--- /dev/null
+++ b/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/EventSubscriber/ActiveTrailSubscriber.php
@@ -0,0 +1,68 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\menu_test\EventSubscriber\ActiveTrailSubscriber.
+ */
+
+namespace Drupal\menu_test\EventSubscriber;
+
+use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+
+/**
+ * Tracks the active trail.
+ */
+class ActiveTrailSubscriber implements EventSubscriberInterface {
+
+  /**
+   * The active trail before redirect.
+   *
+   * @var array
+   */
+  protected $trail = array();
+
+  /**
+   * The state service.
+   *
+   * @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface
+   */
+  protected $state;
+
+  /**
+   * Constructs a new ActiveTrailSubscriber.
+   *
+   * @param \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state
+   *   The state service.
+   */
+  public function __construct(KeyValueStoreInterface $state) {
+    $this->state = $state;
+  }
+
+  /**
+   * Tracks the active trail.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
+   *   The event to process.
+   */
+  public function onKernelRequest(GetResponseEvent $event) {
+    // When requested by one of the MenuTrailTestCase tests, record the initial
+    // active trail during Drupal's bootstrap (before the user is redirected to
+    // a custom 403 or 404 page).
+    if (!$this->trail && $this->state->get('menu_test.record_active_trail') ?: FALSE) {
+      $this->trail = menu_get_active_trail();
+      $this->state->set('menu_test.active_trail_initial', $this->trail);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    $events[KernelEvents::REQUEST][] = array('onKernelRequest');
+    return $events;
+  }
+
+}
diff --git a/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/Theme/TestThemeNegotiator.php b/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/Theme/TestThemeNegotiator.php
index eb4f356..b324d8d 100644
--- a/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/Theme/TestThemeNegotiator.php
+++ b/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/Theme/TestThemeNegotiator.php
@@ -40,4 +40,4 @@ public function determineActiveTheme(Request $request) {
     // causes the page to correctly fall back on using the main site theme.
   }
 
-} 
+}
diff --git a/core/modules/system/tests/modules/menu_test/menu_test.services.yml b/core/modules/system/tests/modules/menu_test/menu_test.services.yml
index b52f8cf..3de0169 100644
--- a/core/modules/system/tests/modules/menu_test/menu_test.services.yml
+++ b/core/modules/system/tests/modules/menu_test/menu_test.services.yml
@@ -4,6 +4,12 @@ services:
     tags:
       - { name: event_subscriber }
 
+  menu_test.active_trail_subscriber:
+    class: Drupal\menu_test\EventSubscriber\ActiveTrailSubscriber
+    arguments: ['@state']
+    tags:
+      - { name: event_subscriber }
+
   theme.negotiator.test_theme:
     class: Drupal\menu_test\Theme\TestThemeNegotiator
     tags:
diff --git a/core/modules/system/tests/modules/theme_test/lib/Drupal/theme_test/Theme/CustomThemeNegotiator.php b/core/modules/system/tests/modules/theme_test/lib/Drupal/theme_test/Theme/CustomThemeNegotiator.php
index 6ca1b71..9c0396e 100644
--- a/core/modules/system/tests/modules/theme_test/lib/Drupal/theme_test/Theme/CustomThemeNegotiator.php
+++ b/core/modules/system/tests/modules/theme_test/lib/Drupal/theme_test/Theme/CustomThemeNegotiator.php
@@ -26,4 +26,4 @@ public function determineActiveTheme(Request $request) {
     }
   }
 
-} 
+}
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/ThemeTest.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/ThemeTest.php
index 452e33f..ee8cc38 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/ThemeTest.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/ThemeTest.php
@@ -25,11 +25,11 @@ function setUp() {
 
     // Make sure we are using distinct default and administrative themes for
     // the duration of these tests.
+    theme_enable(array('bartik', 'seven'));
     \Drupal::config('system.theme')
       ->set('default', 'bartik')
+      ->set('admin', 'seven')
       ->save();
-    theme_enable(array('seven'));
-    \Drupal::config('system.theme')->set('admin', 'seven')->save();
 
     // Create and log in as a user who has permission to add and edit taxonomy
     // terms and view the administrative theme.
diff --git a/core/modules/user/user.info.yml b/core/modules/user/user.info.yml
index 4af3313..45a421a 100644
--- a/core/modules/user/user.info.yml
+++ b/core/modules/user/user.info.yml
@@ -6,5 +6,3 @@ version: VERSION
 core: 8.x
 required: true
 configure: user.admin_index
-dependencies:
-  - field