diff --git a/core/modules/system/lib/Drupal/system/Controller/SystemController.php b/core/modules/system/lib/Drupal/system/Controller/SystemController.php
index fce04b8..283a942 100644
--- a/core/modules/system/lib/Drupal/system/Controller/SystemController.php
+++ b/core/modules/system/lib/Drupal/system/Controller/SystemController.php
@@ -10,13 +10,11 @@
 use Drupal\Core\Controller\ControllerBase;
 use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
 use Drupal\Core\Entity\Query\QueryFactory;
+use Drupal\Core\Extension\ThemeHandlerInterface;
+use Drupal\Core\Form\FormBuilderInterface;
 use Drupal\Core\Theme\ThemeAccessCheck;
-use Drupal\system\Form\ThemeAdminForm;
-use Drupal\Core\Access\CsrfTokenGenerator;
 use Drupal\system\SystemManager;
-use Drupal\Core\Form\FormBuilder;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Symfony\Component\HttpFoundation\RedirectResponse;
 
 /**
  * Returns responses for System routes.
@@ -38,13 +36,6 @@ class SystemController extends ControllerBase implements ContainerInjectionInter
   protected $systemManager;
 
   /**
-   * The Csrf token generator service.
-   *
-   * @var \Drupal\Core\Access\CsrfTokenGenerator
-   */
-  protected $tokenGenerator;
-
-  /**
    * The theme access checker service.
    *
    * @var \Drupal\Core\Theme\ThemeAccessCheck
@@ -54,28 +45,35 @@ class SystemController extends ControllerBase implements ContainerInjectionInter
   /**
    * The form builder service.
    *
-   * @var \Drupal\Core\Form\FormBuilder
+   * @var \Drupal\Core\Form\FormBuilderInterface
    */
   protected $formBuilder;
 
   /**
+   * @var \Drupal\Core\Extension\ThemeHandlerInterface
+   */
+  protected $themeHandler;
+
+  /**
    * Constructs a new SystemController.
    *
    * @param \Drupal\system\SystemManager $systemManager
    *   System manager service.
    * @param \Drupal\Core\Entity\Query\QueryFactory $queryFactory
    *   The entity query object.
-   * @param \Drupal\Core\Access\CsrfTokenGenerator $token_generator
-   *   The token generator service.
    * @param \Drupal\Core\Theme\ThemeAccessCheck $theme_access
    *   The theme access checker service.
+   * @param \Drupal\Core\Form\FormBuilderInterface $form_builder
+   *   The form builder.
+   * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
+   *   The theme handler.
    */
-  public function __construct(SystemManager $systemManager, QueryFactory $queryFactory, CsrfTokenGenerator $token_generator, ThemeAccessCheck $theme_access, FormBuilder $form_builder) {
+  public function __construct(SystemManager $systemManager, QueryFactory $queryFactory, ThemeAccessCheck $theme_access, FormBuilderInterface $form_builder, ThemeHandlerInterface $theme_handler) {
     $this->systemManager = $systemManager;
     $this->queryFactory = $queryFactory;
-    $this->tokenGenerator = $token_generator;
     $this->themeAccess = $theme_access;
     $this->formBuilder = $form_builder;
+    $this->themeHandler = $theme_handler;
   }
 
   /**
@@ -85,9 +83,9 @@ public static function create(ContainerInterface $container) {
     return new static(
       $container->get('system.manager'),
       $container->get('entity.query'),
-      $container->get('csrf_token'),
       $container->get('access_check.theme'),
-      $container->get('form_builder')
+      $container->get('form_builder'),
+      $container->get('theme_handler')
     );
   }
 
@@ -189,7 +187,7 @@ public function systemAdminMenuBlockPage() {
   public function themesPage() {
     $config = $this->config('system.theme');
     // Get current list of themes.
-    $themes = system_rebuild_theme_data();
+    $themes = $this->themeHandler->listInfo();
     uasort($themes, 'system_sort_modules_by_info_name');
 
     $theme_default = $config->get('default');
@@ -301,10 +299,10 @@ public function themesPage() {
 
     // There are two possible theme groups.
     $theme_group_titles = array(
-      'enabled' => format_plural(count($theme_groups['enabled']), 'Enabled theme', 'Enabled themes'),
+      'enabled' => $this->translationManager()->formatPlural(count($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');
+      $theme_group_titles['disabled'] = $this->translationManager()->formatPlural(count($theme_groups['disabled']), 'Disabled theme', 'Disabled themes');
     }
 
     uasort($theme_groups['enabled'], function($a, $b) {