diff -u b/core/core.services.yml b/core/core.services.yml
--- b/core/core.services.yml
+++ b/core/core.services.yml
@@ -114,7 +114,7 @@
       - { name: page_cache_response_policy }
   config.manager:
     class: Drupal\Core\Config\ConfigManager
-    arguments: ['@entity.manager', '@config.factory', '@config.typed', '@string_translation', '@config.storage', '@event_dispatcher', '@module_handler', '@theme_handler']
+    arguments: ['@entity.manager', '@config.factory', '@config.typed', '@string_translation', '@config.storage', '@event_dispatcher', '@module_handler']
   config.factory:
     class: Drupal\Core\Config\ConfigFactory
     tags:
diff -u b/core/lib/Drupal/Core/Config/ConfigManager.php b/core/lib/Drupal/Core/Config/ConfigManager.php
--- b/core/lib/Drupal/Core/Config/ConfigManager.php
+++ b/core/lib/Drupal/Core/Config/ConfigManager.php
@@ -68,13 +68,6 @@
   protected $moduleHandler;
 
   /**
-   * The theme handler service.
-   *
-   * @var \Drupal\Core\Extension\ThemeHandlerInterface
-   */
-  protected $themeHandler;
-
-  /**
    * The configuration collection info.
    *
    * @var \Drupal\Core\Config\ConfigCollectionInfo
@@ -103,8 +96,10 @@
    *   The active configuration storage.
    * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
    *   The event dispatcher.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler.
    */
-  public function __construct(EntityManagerInterface $entity_manager, ConfigFactoryInterface $config_factory, TypedConfigManagerInterface $typed_config_manager, TranslationManager $string_translation, StorageInterface $active_storage, EventDispatcherInterface $event_dispatcher, ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler) {
+  public function __construct(EntityManagerInterface $entity_manager, ConfigFactoryInterface $config_factory, TypedConfigManagerInterface $typed_config_manager, TranslationManager $string_translation, StorageInterface $active_storage, EventDispatcherInterface $event_dispatcher, ModuleHandlerInterface $module_handler) {
     $this->entityManager = $entity_manager;
     $this->configFactory = $config_factory;
     $this->typedConfigManager = $typed_config_manager;
@@ -112,7 +107,6 @@
     $this->activeStorage = $active_storage;
     $this->eventDispatcher = $event_dispatcher;
     $this->moduleHandler = $module_handler;
-    $this->themeHandler = $theme_handler;
   }
 
   /**
@@ -351,7 +345,9 @@
    *   Whether or not all modules and themes are enabled.
    */
   protected function validateConfigEntityDependentThemesExistence(array $names) {
-    $themes = $this->themeHandler->listInfo();
+    // @todo ThemeHandler cannot be injected into ConfigManager, since that
+    // causes a circular service dependency.
+    $themes = \Drupal::service('theme_handler')->listInfo();
     foreach ($names as $theme_name) {
       if (!isset($themes[$theme_name])) {
         return FALSE;
diff -u b/core/modules/config/src/Form/ConfigSingleImportForm.php b/core/modules/config/src/Form/ConfigSingleImportForm.php
--- b/core/modules/config/src/Form/ConfigSingleImportForm.php
+++ b/core/modules/config/src/Form/ConfigSingleImportForm.php
@@ -202,7 +202,7 @@
     // Validate existence of configuration entity dependents.
     if (!empty($data['dependencies'])) {
       if (!$this->configManager->validateConfigEntityDependentsExistence($data['dependencies'])) {
-        $this->setFormError('import', $form_state, $this->t('Missing dependencies have been found. Import them first.'));
+        $form_state->setErrorByName('import', $this->t('Missing dependencies have been found. Import them first.'));
       }
     }
 
diff -u b/core/modules/config/src/Tests/ConfigDependencyTest.php b/core/modules/config/src/Tests/ConfigDependencyTest.php
--- b/core/modules/config/src/Tests/ConfigDependencyTest.php
+++ b/core/modules/config/src/Tests/ConfigDependencyTest.php
@@ -24,6 +24,17 @@
   public static $modules = array('system', 'config_test');
 
   /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    // Install Stark theme, as \Drupal\simpletest\KernelTestBase doesn't install
+    // it be default.
+    \Drupal::service('theme_handler')->install(array('stark'));
+  }
+
+  /**
    * Tests that calculating dependencies for system module.
    */
   public function testNonEntity() {