diff -u b/core/modules/system/src/Controller/ThemeController.php b/core/modules/system/src/Controller/ThemeController.php
--- b/core/modules/system/src/Controller/ThemeController.php
+++ b/core/modules/system/src/Controller/ThemeController.php
@@ -7,7 +7,6 @@
 use Drupal\Core\Config\UnmetDependenciesException;
 use Drupal\Core\Controller\ControllerBase;
 use Drupal\Core\Extension\ThemeHandlerInterface;
-use Drupal\Core\Messenger\MessengerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
@@ -25,26 +24,16 @@
   protected $themeHandler;
 
   /**
-   * The messenger.
-   *
-   * @var \Drupal\Core\Messenger\MessengerInterface
-   */
-  protected $messenger;
-
-  /**
    * Constructs a new ThemeController.
    *
    * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
    *   The theme handler.
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The config factory.
-   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
-   *   The messenger.
    */
-  public function __construct(ThemeHandlerInterface $theme_handler, ConfigFactoryInterface $config_factory, MessengerInterface $messenger) {
+  public function __construct(ThemeHandlerInterface $theme_handler, ConfigFactoryInterface $config_factory) {
     $this->themeHandler = $theme_handler;
     $this->configFactory = $config_factory;
-    $this->messenger = $messenger;
   }
 
   /**
@@ -53,8 +42,7 @@
   public static function create(ContainerInterface $container) {
     return new static(
       $container->get('theme_handler'),
-      $container->get('config.factory'),
-      $container->get('messenger')
+      $container->get('config.factory')
     );
   }
 
diff -u b/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php b/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php
--- b/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php
+++ b/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php
@@ -46,6 +46,19 @@
   }
 
   /**
+   * Tests installing a theme with existing module dependencies.
+   */
+  public function testInstallModuleWithAlreadyInstalledDependencies() {
+    $this->drupalGet('admin/appearance');
+    $themeXpath = '//h3[contains(text(), "test theme depending on already installed module")]';
+    $elements = $this->xpath($themeXpath);
+    $this->assertCount(1, $elements);
+    $this->getSession()->getDriver()->click('//h3[contains(text(), "test theme depending on already installed module")]/../ul/li[1]/a');
+    $this->assertSession()->addressEquals('admin/appearance');
+    $this->assertSession()->pageTextContains('The test theme depending on already installed module theme has been installed.');
+  }
+
+  /**
    * Tests installing a theme with missing module dependencies.
    */
   public function testInstallModuleWithMissingDependencies() {
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/system/tests/themes/test_theme_depending_on_already_installed_module/test_theme_depending_on_already_installed_module.info.yml
@@ -0,0 +1,5 @@
+name: test theme depending on already installed module
+type: theme
+core: 8.x
+dependencies:
+  - node