diff --git c/core/modules/system/lib/Drupal/system/Controller/ThemeController.php w/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
index 39749e8..b498713 100644
--- c/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
+++ w/core/modules/system/lib/Drupal/system/Controller/ThemeController.php
@@ -7,8 +7,9 @@
 
 namespace Drupal\system\Controller;
 
-use Drupal\Core\Config\Config;
 use Drupal\Core\Controller\ControllerBase;
+use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
 use Drupal\Core\Access\CsrfTokenGenerator;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
@@ -17,9 +18,34 @@
 /**
  * Controller for theme handling.
  */
-class ThemeController extends ControllerBase {
+class ThemeController extends ControllerBase implements ContainerInjectionInterface {
 
   /**
+   * Token generator service.
+   *
+   * @var \Drupal\Core\Access\CsrfTokenGenerator
+   */
+  protected $tokenGenerator;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('csrf_token')
+    );
+  }
+
+  /**
+   * Constructs a Theme Controller Object.
+   *
+   * @param \Drupal\Core\Access\CsrfTokenGenerator $token_generator
+   *   Token Generator Service.
+   */
+  public function __construct(CsrfTokenGenerator $token_generator) {
+    $this->tokenGenerator = $token_generator;
+  }
+  /**
    * Disables a theme.
    *
    * @param \Symfony\Component\HttpFoundation\Request $request
@@ -37,7 +63,7 @@ public function disable(Request $request) {
     $token = $request->get('token');
     $config = $this->config('system.theme');
 
-    if (isset($theme) && isset($token) && $this->getTokenGenerator()->validate($token, 'system-theme-operation-link')) {
+    if (isset($theme) && isset($token) && $this->tokenGenerator->validate($token, 'system-theme-operation-link')) {
       // Get current list of themes.
       $themes = list_themes();
 
@@ -80,7 +106,7 @@ public function enable(Request $request) {
     $theme = $request->get('theme');
     $token = $request->get('token');
 
-    if (isset($theme) && isset($token) && $this->getTokenGenerator()->validate($token, 'system-theme-operation-link')) {
+    if (isset($theme) && isset($token) && $this->tokenGenerator->validate($token, 'system-theme-operation-link')) {
       // Get current list of themes.
       $themes = list_themes(TRUE);
 
@@ -118,7 +144,7 @@ public function defaultTheme(Request $request) {
 
     $theme = $request->query->get('theme');
     $token = $request->query->get('token');
-    if (isset($theme) && isset($token) && $this->getTokenGenerator()->validate($token, 'system-theme-operation-link')) {
+    if (isset($theme) && isset($token) && $this->tokenGenerator->validate($token, 'system-theme-operation-link')) {
       // Get current list of themes.
       $themes = list_themes();
 
@@ -162,17 +188,4 @@ public function defaultTheme(Request $request) {
     throw new AccessDeniedHttpException();
   }
 
-  /**
-   * Gets Token Generator Service.
-   *
-   * @return \Drupal\Core\Access\CsrfTokenGenerator
-   **/
-  public function getTokenGenerator()
-  {
-    if (empty($this->tokenGenerator)) {
-      $this->tokenGenerator = $this->container->get('csrf_token');
-    }
-    return $this->tokenGenerator;
-  }
-
 }
diff --git c/core/modules/system/system.admin.inc w/core/modules/system/system.admin.inc
index 9db20be..8245cb5 100644
--- c/core/modules/system/system.admin.inc
+++ w/core/modules/system/system.admin.inc
@@ -176,57 +176,6 @@ function system_themes_admin_form_submit($form, &$form_state) {
 }
 
 /**
- * Menu callback; Set the default theme.
- */
-function system_theme_default() {
-  $request = Drupal::request();
-  $theme = $request->get('theme');
-  $token = $request->get('token');
-  if (!empty($theme) && !empty($token) && drupal_valid_token($token, 'system-theme-operation-link')) {
-    // Get current list of themes.
-    $themes = list_themes();
-
-    // Check if the specified theme is one recognized by the system.
-    if (!empty($themes[$theme])) {
-      // Enable the theme if it is currently disabled.
-      if (empty($themes[$theme]->status)) {
-       theme_enable(array($theme));
-      }
-      // Set the default theme.
-      Drupal::config('system.theme')
-        ->set('default', $theme)
-        ->save();
-
-      // Rebuild the menu. This duplicates the menu_router_rebuild() in
-      // theme_enable(). However, modules must know the current default theme in
-      // order to use this information in hook_menu() or hook_menu_alter()
-      // implementations, and doing the variable_set() before the theme_enable()
-      // could result in a race condition where the theme is default but not
-      // enabled.
-      menu_router_rebuild();
-
-      // The status message depends on whether an admin theme is currently in use:
-      // a value of 0 means the admin theme is set to be the default theme.
-      $admin_theme = Drupal::config('system.theme')->get('admin');
-      if ($admin_theme != 0 && $admin_theme != $theme) {
-        drupal_set_message(t('Please note that the administration theme is still set to the %admin_theme theme; consequently, the theme on this page remains unchanged. All non-administrative sections of the site, however, will show the selected %selected_theme theme by default.', array(
-          '%admin_theme' => $themes[$admin_theme]->info['name'],
-          '%selected_theme' => $themes[$theme]->info['name'],
-        )));
-      }
-      else {
-        drupal_set_message(t('%theme is now the default theme.', array('%theme' => $themes[$theme]->info['name'])));
-      }
-    }
-    else {
-      drupal_set_message(t('The %theme theme was not found.', array('%theme' => $theme)), 'error');
-    }
-    return new RedirectResponse(url('admin/appearance', array('absolute' => TRUE)));
-  }
-  throw new AccessDeniedHttpException();
-}
-
-/**
  * Recursively check compatibility.
  *
  * @param $incompatible