diff --git a/core/lib/Drupal/Core/ControllerResolver.php b/core/lib/Drupal/Core/ControllerResolver.php
index cf455cf..2175eb1 100644
--- a/core/lib/Drupal/Core/ControllerResolver.php
+++ b/core/lib/Drupal/Core/ControllerResolver.php
@@ -80,16 +80,11 @@ protected function createController($controller) {
       if (!class_exists($class)) {
         throw new \InvalidArgumentException(sprintf('Class "%s" does not exist.', $class));
       }
-      $controller = new $class();
-    }
-    // class:factory:method
-    elseif ($count == 2) {
-      list($class, $factory_method, $method) = explode(':', $controller, 3);
-      if (method_exists($class, $factory_method)) {
-        $controller = $class::$factory_method($this->container);
+      if (in_array('Drupal\Core\ControllerInterface', class_implements($class))) {
+        $controller = $class::create($this->container);
       }
       else {
-        throw new \InvalidArgumentException(sprintf('Factory method "%s::%s" does not exist.', $class, $factory_method));
+        $controller = new $class();
       }
     }
     else {
diff --git a/core/modules/user/lib/Drupal/user/UserAutocompleteController.php b/core/modules/user/lib/Drupal/user/UserAutocompleteController.php
index ae472e2..1081d65 100644
--- a/core/modules/user/lib/Drupal/user/UserAutocompleteController.php
+++ b/core/modules/user/lib/Drupal/user/UserAutocompleteController.php
@@ -8,12 +8,14 @@
 
 use Symfony\Component\HttpFoundation\JsonResponse;
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\DependencyInjection\Container;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+use Drupal\Core\ControllerInterface;
 
 /**
  * Controller routines for taxonomy user routes.
  */
-class UserAutocompleteController {
+class UserAutocompleteController implements ControllerInterface {
 
   /**
    * The user autocomplete helper class to find matching user names.
@@ -33,9 +35,9 @@ public function __construct(UserAutocomplete $user_autocomplete) {
   }
 
   /**
-   * @todo.
+   * Implements \Drupal\ControllerInterface::create().
    */
-  public static function create(Container $container) {
+  public static function create(ContainerInterface $container) {
     return new static(
       $container->get('user.autocomplete')
     );
diff --git a/core/modules/user/user.routing.yml b/core/modules/user/user.routing.yml
index ad70759..34b6059 100644
--- a/core/modules/user/user.routing.yml
+++ b/core/modules/user/user.routing.yml
@@ -8,13 +8,13 @@ user_register:
 user_autocomplete:
   pattern: '/user/autocomplete'
   defaults:
-    _controller: 'user.autocomplete_controller:autocompleteUser'
+    _controller: '\Drupal\user\UserAutocompleteController::autocompleteUser'
   requirements:
     _permission: 'access user profiles'
 
 user_autocomplete_anonymous:
   pattern: '/user/autocomplete/anonymous'
   defaults:
-    _controller: 'user.autocomplete_controller:autocompleteUserAnonymous'
+    _controller: '\Drupal\user\UserAutocompleteController::autocompleteUserAnonymous'
   requirements:
     _permission: 'access user profiles'