Issue #2165475 by damiankloip, dawehner, martin107, tim.plunkett, jibran, xjm, Jalandhar: Provide a generic class resolver.

16 files changed, 252 insertions, 104 deletions

diff --git a/core/core.services.yml b/core/core.services.yml
index c4b55ac..0543272 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -121,7 +121,7 @@ services:
     arguments: [default]
   form_builder:
     class: Drupal\Core\Form\FormBuilder
-    arguments: ['@form_validator', '@form_submitter', '@module_handler', '@keyvalue.expirable', '@event_dispatcher', '@request_stack', '@?csrf_token', '@?http_kernel']
+    arguments: ['@form_validator', '@form_submitter', '@module_handler', '@keyvalue.expirable', '@event_dispatcher', '@request_stack', '@class_resolver', '@?csrf_token', '@?http_kernel']
   form_validator:
     class: Drupal\Core\Form\FormValidator
     arguments: ['@request_stack', '@string_translation', '@csrf_token']
@@ -224,7 +224,7 @@ services:
     arguments: ['@config.factory', '@module_handler', '@state', '@info_parser', '@config.installer', '@router.builder']
   entity.manager:
     class: Drupal\Core\Entity\EntityManager
-    arguments: ['@container.namespaces', '@module_handler', '@cache.discovery', '@language_manager', '@string_translation']
+    arguments: ['@container.namespaces', '@module_handler', '@cache.discovery', '@language_manager', '@string_translation', '@class_resolver']
     parent: container.trait
     tags:
       - { name: plugin_manager_cache_clear }
@@ -270,8 +270,11 @@ services:
     arguments: ['@service_container']
   controller_resolver:
     class: Drupal\Core\Controller\ControllerResolver
-    arguments: ['@logger.channel.default']
-    parent: container.trait
+    arguments: ['@class_resolver', '@logger.channel.default']
+  class_resolver:
+    class: Drupal\Core\DependencyInjection\ClassResolver
+    calls:
+      - [setContainer, ['@service_container']]
   title_resolver:
     class: Drupal\Core\Controller\TitleResolver
     arguments: ['@controller_resolver', '@string_translation']
@@ -476,7 +479,7 @@ services:
       - { name: event_subscriber }
   route_content_form_controller_subscriber:
     class: Drupal\Core\EventSubscriber\ContentFormControllerSubscriber
-    arguments: ['@controller_resolver', '@form_builder']
+    arguments: ['@class_resolver', '@controller_resolver', '@form_builder']
     parent: container.trait
     tags:
       - { name: event_subscriber }
@@ -496,7 +499,7 @@ services:
     arguments: ['@controller_resolver', '@ajax_response_renderer']
   controller.entityform:
     class: Drupal\Core\Entity\HtmlEntityFormController
-    arguments: ['@controller_resolver', '@service_container', '@entity.manager']
+    arguments: ['@class_resolver', '@controller_resolver', '@service_container', '@entity.manager']
   controller.dialog:
     class: Drupal\Core\Controller\DialogController
     arguments: ['@controller_resolver', '@title_resolver']
diff --git a/core/lib/Drupal/Core/Controller/ControllerResolver.php b/core/lib/Drupal/Core/Controller/ControllerResolver.php
index c80242c..f165018 100644
--- a/core/lib/Drupal/Core/Controller/ControllerResolver.php
+++ b/core/lib/Drupal/Core/Controller/ControllerResolver.php
@@ -10,8 +10,7 @@ namespace Drupal\Core\Controller;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Controller\ControllerResolver as BaseControllerResolver;
-use Symfony\Component\DependencyInjection\ContainerAwareInterface;
-use Symfony\Component\DependencyInjection\ContainerAwareTrait;
+use Drupal\Core\DependencyInjection\ClassResolverInterface;
 
 /**
  * ControllerResolver to enhance controllers beyond Symfony's basic handling.
@@ -28,9 +27,7 @@ use Symfony\Component\DependencyInjection\ContainerAwareTrait;
  *    controller by using a service:method notation (Symfony uses the same
  *    convention).
  */
-class ControllerResolver extends BaseControllerResolver implements ControllerResolverInterface, ContainerAwareInterface {
-
-   use ContainerAwareTrait;
+class ControllerResolver extends BaseControllerResolver implements ControllerResolverInterface {
 
   /**
    * The PSR-3 logger. (optional)
@@ -40,12 +37,23 @@ class ControllerResolver extends BaseControllerResolver implements ControllerRes
   protected $logger;
 
   /**
+   * The class resolver.
+   *
+   * @var \Drupal\Core\DependencyInjection\ClassResolverInterface
+   */
+  protected $classResolver;
+
+  /**
    * Constructs a new ControllerResolver.
    *
+   * @param \Drupal\Core\DependencyInjection\ClassResolverInterface $class_resolver
+   *   The class resolver.
    * @param \Psr\Log\LoggerInterface $logger
    *   (optional) A LoggerInterface instance.
    */
-  public function __construct(LoggerInterface $logger = NULL) {
+  public function __construct(ClassResolverInterface $class_resolver, LoggerInterface $logger = NULL) {
+    $this->classResolver = $class_resolver;
+
     parent::__construct($logger);
   }
 
@@ -109,31 +117,17 @@ class ControllerResolver extends BaseControllerResolver implements ControllerRes
     // Controller in the service:method notation.
     $count = substr_count($controller, ':');
     if ($count == 1) {
-      list($service, $method) = explode(':', $controller, 2);
-      return array($this->container->get($service), $method);
+      list($class_or_service, $method) = explode(':', $controller, 2);
     }
-
     // Controller in the class::method notation.
-    if (strpos($controller, '::') !== FALSE) {
-      list($class, $method) = explode('::', $controller, 2);
-      if (!class_exists($class)) {
-        throw new \InvalidArgumentException(sprintf('Class "%s" does not exist.', $class));
-      }
-      // @todo Remove the second in_array() once that interface has been removed.
-      if (in_array('Drupal\Core\DependencyInjection\ContainerInjectionInterface', class_implements($class))) {
-        $controller = $class::create($this->container);
-      }
-      else {
-        $controller = new $class();
-      }
+    elseif (strpos($controller, '::') !== FALSE) {
+      list($class_or_service, $method) = explode('::', $controller, 2);
     }
     else {
       throw new \LogicException(sprintf('Unable to parse the controller name "%s".', $controller));
     }
 
-    if ($controller instanceof ContainerAwareInterface) {
-      $controller->setContainer($this->container);
-    }
+    $controller = $this->classResolver->getInstanceFromDefinition($class_or_service);
 
     return array($controller, $method);
   }
diff --git a/core/lib/Drupal/Core/Controller/FormController.php b/core/lib/Drupal/Core/Controller/FormController.php
index 5296a4b..5fec415 100644
--- a/core/lib/Drupal/Core/Controller/FormController.php
+++ b/core/lib/Drupal/Core/Controller/FormController.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Controller;
 
 use Drupal\Core\DependencyInjection\DependencySerialization;
+use Drupal\Core\Controller\ControllerResolverInterface;
 use Drupal\Core\Form\FormBuilderInterface;
 use Symfony\Component\HttpFoundation\Request;
 
@@ -30,7 +31,7 @@ abstract class FormController extends DependencySerialization {
    *
    * @var \Drupal\Core\Controller\ControllerResolverInterface
    */
-  protected $resolver;
+  protected $controllerResolver;
 
   /**
    * The form builder.
@@ -42,13 +43,13 @@ abstract class FormController extends DependencySerialization {
   /**
    * Constructs a new \Drupal\Core\Controller\FormController object.
    *
-   * @param \Drupal\Core\Controller\ControllerResolverInterface $resolver
+   * @param \Drupal\Core\Controller\ControllerResolverInterface $controller_resolver
    *   The controller resolver.
    * @param \Drupal\Core\Form\FormBuilderInterface $form_builder
    *   The form builder.
    */
-  public function __construct(ControllerResolverInterface $resolver, FormBuilderInterface $form_builder) {
-    $this->resolver = $resolver;
+  public function __construct(ControllerResolverInterface $controller_resolver, FormBuilderInterface $form_builder) {
+    $this->controllerResolver = $controller_resolver;
     $this->formBuilder = $form_builder;
   }
 
@@ -69,7 +70,7 @@ abstract class FormController extends DependencySerialization {
     $form_state = array();
     $request->attributes->set('form', array());
     $request->attributes->set('form_state', $form_state);
-    $args = $this->resolver->getArguments($request, array($form_object, 'buildForm'));
+    $args = $this->controllerResolver->getArguments($request, array($form_object, 'buildForm'));
     $request->attributes->remove('form');
     $request->attributes->remove('form_state');
 
diff --git a/core/lib/Drupal/Core/Controller/HtmlFormController.php b/core/lib/Drupal/Core/Controller/HtmlFormController.php
index 2e92c80..c7525b1 100644
--- a/core/lib/Drupal/Core/Controller/HtmlFormController.php
+++ b/core/lib/Drupal/Core/Controller/HtmlFormController.php
@@ -10,6 +10,8 @@ namespace Drupal\Core\Controller;
 use Drupal\Core\Form\FormBuilderInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\DependencyInjection\ClassResolverInterface;
+use Drupal\Core\Controller\ControllerResolverInterface;
 
 /**
  * Wrapping controller for forms that serve as the main page body.
@@ -31,10 +33,18 @@ class HtmlFormController extends FormController {
   protected $formClass;
 
   /**
+   * The class resolver.
+   *
+   * @var \Drupal\Core\DependencyInjection\ClassResolverInterface;
+   */
+  protected $classResolver;
+
+  /**
    * Constructs a new \Drupal\Core\Routing\Enhancer\FormEnhancer object.
    */
-  public function __construct(ControllerResolverInterface $resolver, ContainerInterface $container, $class, FormBuilderInterface $form_builder) {
-    parent::__construct($resolver, $form_builder);
+  public function __construct(ClassResolverInterface $class_resolver, ControllerResolverInterface $controller_resolver, ContainerInterface $container, $class, FormBuilderInterface $form_builder) {
+    parent::__construct($controller_resolver, $form_builder);
+    $this->classResolver = $class_resolver;
     $this->container = $container;
     $this->formDefinition = $class;
   }
@@ -51,17 +61,7 @@ class HtmlFormController extends FormController {
    *   The form object to use.
    */
   protected function getFormObject(Request $request, $form_arg) {
-    // If this is a class, instantiate it.
-    if (class_exists($form_arg)) {
-      if (in_array('Drupal\Core\DependencyInjection\ContainerInjectionInterface', class_implements($form_arg))) {
-        return $form_arg::create($this->container);
-      }
-
-      return new $form_arg();
-    }
-
-    // Otherwise, it is a service.
-    return $this->container->get($form_arg);
+    return $this->classResolver->getInstanceFromDefinition($form_arg);
   }
 
 }
diff --git a/core/lib/Drupal/Core/DependencyInjection/ClassResolver.php b/core/lib/Drupal/Core/DependencyInjection/ClassResolver.php
new file mode 100644
index 0000000..997630d
--- /dev/null
+++ b/core/lib/Drupal/Core/DependencyInjection/ClassResolver.php
@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\DependencyInjection\ClassResolver.
+ */
+
+namespace Drupal\Core\DependencyInjection;
+
+use Symfony\Component\DependencyInjection\ContainerAwareTrait;
+use Symfony\Component\DependencyInjection\ContainerAwareInterface;
+
+/**
+ * Implements the class resolver interface supporting class names and services.
+ */
+class ClassResolver implements ClassResolverInterface, ContainerAwareInterface {
+
+  use ContainerAwareTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getInstanceFromDefinition($definition) {
+    if ($this->container->has($definition)) {
+      $instance = $this->container->get($definition);
+    }
+    else {
+      if (!class_exists($definition)) {
+        throw new \InvalidArgumentException(sprintf('Class "%s" does not exist.', $definition));
+      }
+
+      if (is_subclass_of($definition, 'Drupal\Core\DependencyInjection\ContainerInjectionInterface')) {
+        $instance = $definition::create($this->container);
+      }
+      else {
+        $instance = new $definition();
+      }
+    }
+
+    if ($instance instanceof ContainerAwareInterface) {
+      $instance->setContainer($this->container);
+    }
+
+    return $instance;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/DependencyInjection/ClassResolverInterface.php b/core/lib/Drupal/Core/DependencyInjection/ClassResolverInterface.php
new file mode 100644
index 0000000..7acfec1
--- /dev/null
+++ b/core/lib/Drupal/Core/DependencyInjection/ClassResolverInterface.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\DependencyInjection\ClassResolverInterface.
+ */
+
+namespace Drupal\Core\DependencyInjection;
+
+/**
+ * Provides an interface to get a instance of a class with dependency injection.
+ */
+interface ClassResolverInterface {
+
+  /**
+   * Returns a class instance with a given class definition.
+   *
+   * In contrast to controllers you don't specify a method.
+   *
+   * @param string $definition
+   *   A class name or service name.
+   *
+   * @throws \InvalidArgumentException
+   *   If $class is not a valid service identifer and the class does not exist.
+   *
+   * @return object
+   *   The instance of the class.
+  */
+  public function getInstanceFromDefinition($definition);
+
+}
diff --git a/core/lib/Drupal/Core/Entity/EntityManager.php b/core/lib/Drupal/Core/Entity/EntityManager.php
index 87e529e..32c9aae 100644
--- a/core/lib/Drupal/Core/Entity/EntityManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityManager.php
@@ -10,6 +10,7 @@ namespace Drupal\Core\Entity;
 use Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException;
 use Drupal\Component\Plugin\Exception\PluginNotFoundException;
 use Drupal\Component\Utility\String;
+use Drupal\Core\DependencyInjection\ClassResolverInterface;
 use Drupal\Core\Field\FieldDefinition;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheBackendInterface;
@@ -88,6 +89,13 @@ class EntityManager extends DefaultPluginManager implements EntityManagerInterfa
   protected $translationManager;
 
   /**
+   * The class resolver.
+   *
+   * @var \Drupal\Core\DependencyInjection\ClassResolverInterface
+   */
+  protected $classResolver;
+
+  /**
    * Static cache of bundle information.
    *
    * @var array
@@ -125,14 +133,17 @@ class EntityManager extends DefaultPluginManager implements EntityManagerInterfa
    *   The language manager.
    * @param \Drupal\Core\StringTranslation\TranslationInterface $translation_manager
    *   The string translationManager.
+   * @param \Drupal\Core\DependencyInjection\ClassResolverInterface $class_resolver
+   *   The class resolver.
    */
-  public function __construct(\Traversable $namespaces, ModuleHandlerInterface $module_handler, CacheBackendInterface $cache, LanguageManagerInterface $language_manager, TranslationInterface $translation_manager) {
+  public function __construct(\Traversable $namespaces, ModuleHandlerInterface $module_handler, CacheBackendInterface $cache, LanguageManagerInterface $language_manager, TranslationInterface $translation_manager, ClassResolverInterface $class_resolver) {
     parent::__construct('Entity', $namespaces, $module_handler, 'Drupal\Core\Entity\Annotation\EntityType');
 
     $this->setCacheBackend($cache, $language_manager, 'entity_type:', array('entity_types' => TRUE));
     $this->alterInfo('entity_type');
 
     $this->translationManager = $translation_manager;
+    $this->classResolver = $class_resolver;
   }
 
   /**
@@ -213,12 +224,8 @@ class EntityManager extends DefaultPluginManager implements EntityManagerInterfa
       if (!$class = $this->getDefinition($entity_type, TRUE)->getFormClass($operation)) {
         throw new InvalidPluginDefinitionException($entity_type, sprintf('The "%s" entity type did not specify a "%s" form class.', $entity_type, $operation));
       }
-      if (in_array('Drupal\Core\DependencyInjection\ContainerInjectionInterface', class_implements($class))) {
-        $controller = $class::create($this->container);
-      }
-      else {
-        $controller = new $class();
-      }
+
+      $controller = $this->classResolver->getInstanceFromDefinition($class);
 
       $controller
         ->setStringTranslation($this->translationManager)
diff --git a/core/lib/Drupal/Core/EventSubscriber/ContentFormControllerSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/ContentFormControllerSubscriber.php
index b64e6a4..4f84925 100644
--- a/core/lib/Drupal/Core/EventSubscriber/ContentFormControllerSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ContentFormControllerSubscriber.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\EventSubscriber;
 
 use Drupal\Core\Controller\HtmlFormController;
+use Drupal\Core\DependencyInjection\ClassResolverInterface;
 use Drupal\Core\Controller\ControllerResolverInterface;
 use Drupal\Core\Form\FormBuilderInterface;
 use Symfony\Component\HttpKernel\Event\GetResponseEvent;
@@ -26,9 +27,9 @@ class ContentFormControllerSubscriber implements EventSubscriberInterface, Conta
   /**
    * The controller resolver.
    *
-   * @var \Drupal\Core\Controller\ControllerResolverInterface
+   * @var  \Drupal\Core\DependencyInjection\ClassResolverInterface.
    */
-  protected $resolver;
+  protected $classResolver;
 
   /**
    * The form builder.
@@ -40,13 +41,16 @@ class ContentFormControllerSubscriber implements EventSubscriberInterface, Conta
   /**
    * Constructs a new ContentFormControllerSubscriber object.
    *
-   * @param \Drupal\Core\Controller\ControllerResolverInterface $resolver
-   *   The controller resolver.
+   * @param  \Drupal\Core\DependencyInjection\ClassResolverInterface $class_resolver
+   *   The class resolver.
+   * @param \Drupal\Core\Controller\ControllerResolverInterface $controller_resolver
+   *   The class resolver.
    * @param \Drupal\Core\Form\FormBuilderInterface $form_builder
    *   The form builder.
    */
-  public function __construct(ControllerResolverInterface $resolver, FormBuilderInterface $form_builder) {
-    $this->resolver = $resolver;
+  public function __construct(ClassResolverInterface $class_resolver, ControllerResolverInterface $controller_resolver, FormBuilderInterface $form_builder) {
+    $this->classResolver = $class_resolver;
+    $this->controllerResolver = $controller_resolver;
     $this->formBuilder = $form_builder;
   }
 
@@ -60,7 +64,7 @@ class ContentFormControllerSubscriber implements EventSubscriberInterface, Conta
     $request = $event->getRequest();
 
     if ($form = $request->attributes->get('_form')) {
-      $wrapper = new HtmlFormController($this->resolver, $this->container, $form, $this->formBuilder);
+      $wrapper = new HtmlFormController($this->classResolver, $this->controllerResolver, $this->container, $form, $this->formBuilder);
       $request->attributes->set('_content', array($wrapper, 'getContentResult'));
     }
   }
diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index ebaf19b..d3bedc1 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -11,6 +11,7 @@ use Drupal\Component\Utility\Crypt;
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Component\Utility\UrlHelper;
 use Drupal\Core\Access\CsrfTokenGenerator;
+use Drupal\Core\DependencyInjection\ClassResolverInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\HttpKernel;
 use Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface;
@@ -71,6 +72,13 @@ class FormBuilder implements FormBuilderInterface, FormValidatorInterface, FormS
   protected $httpKernel;
 
   /**
+   * The class resolver.
+   *
+   * @var \Drupal\Core\DependencyInjection\ClassResolverInterface
+   */
+  protected $classResolver;
+
+  /**
    * The current user.
    *
    * @var \Drupal\Core\Session\AccountInterface
@@ -102,18 +110,21 @@ class FormBuilder implements FormBuilderInterface, FormValidatorInterface, FormS
    *   The event dispatcher.
    * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
    *   The request stack.
+   * @param \Drupal\Core\DependencyInjection\ClassResolverInterface $class_resolver
+   *   The class resolver.
    * @param \Drupal\Core\Access\CsrfTokenGenerator $csrf_token
    *   The CSRF token generator.
    * @param \Drupal\Core\HttpKernel $http_kernel
    *   The HTTP kernel.
    */
-  public function __construct(FormValidatorInterface $form_validator, FormSubmitterInterface $form_submitter, ModuleHandlerInterface $module_handler, KeyValueExpirableFactoryInterface $key_value_expirable_factory, EventDispatcherInterface $event_dispatcher, RequestStack $request_stack, CsrfTokenGenerator $csrf_token = NULL, HttpKernel $http_kernel = NULL) {
+  public function __construct(FormValidatorInterface $form_validator, FormSubmitterInterface $form_submitter, ModuleHandlerInterface $module_handler, KeyValueExpirableFactoryInterface $key_value_expirable_factory, EventDispatcherInterface $event_dispatcher, RequestStack $request_stack, ClassResolverInterface $class_resolver, CsrfTokenGenerator $csrf_token = NULL, HttpKernel $http_kernel = NULL) {
     $this->formValidator = $form_validator;
     $this->formSubmitter = $form_submitter;
     $this->moduleHandler = $module_handler;
     $this->keyValueExpirableFactory = $key_value_expirable_factory;
     $this->eventDispatcher = $event_dispatcher;
     $this->requestStack = $request_stack;
+    $this->classResolver = $class_resolver;
     $this->csrfToken = $csrf_token;
     $this->httpKernel = $http_kernel;
   }
@@ -122,15 +133,12 @@ class FormBuilder implements FormBuilderInterface, FormValidatorInterface, FormS
    * {@inheritdoc}
    */
   public function getFormId($form_arg, &$form_state) {
-    // If the $form_arg is the name of a class, instantiate it.
+    // If the $form_arg is the name of a class, instantiate it. Don't allow
+    // arbitrary strings to be passed to the class resolver.
     if (is_string($form_arg) && class_exists($form_arg)) {
-      if (in_array('Drupal\Core\DependencyInjection\ContainerInjectionInterface', class_implements($form_arg))) {
-        $form_arg = $form_arg::create(\Drupal::getContainer());
-      }
-      else {
-        $form_arg = new $form_arg();
-      }
+      $form_arg = $this->classResolver->getInstanceFromDefinition($form_arg);
     }
+
     // If the $form_arg implements \Drupal\Core\Form\FormInterface, add that as
     // the callback object and determine the form ID.
     if (is_object($form_arg) && $form_arg instanceof FormInterface) {
diff --git a/core/modules/views/lib/Drupal/views/Form/ViewsForm.php b/core/modules/views/lib/Drupal/views/Form/ViewsForm.php
index cc01f8d..45f1730 100644
--- a/core/modules/views/lib/Drupal/views/Form/ViewsForm.php
+++ b/core/modules/views/lib/Drupal/views/Form/ViewsForm.php
@@ -9,6 +9,7 @@ namespace Drupal\views\Form;
 
 use Drupal\Component\Utility\UrlHelper;
 use Drupal\Core\Controller\ControllerResolverInterface;
+use Drupal\Core\DependencyInjection\ClassResolverInterface;
 use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
 use Drupal\Core\DependencyInjection\DependencySerialization;
 use Drupal\Core\Form\FormInterface;
@@ -28,11 +29,11 @@ use Symfony\Component\HttpFoundation\Request;
 class ViewsForm extends DependencySerialization implements FormInterface, ContainerInjectionInterface {
 
   /**
-   * The controller resolver to get the subform form objects.
+   * The class resolver to get the subform form objects.
    *
-   * @var \Drupal\Core\Controller\ControllerResolverInterface
+   * @var \Drupal\Core\DependencyInjection\ClassResolverInterface
    */
-  protected $controllerResolver;
+  protected $classResolver;
 
   /**
    * The current request.
@@ -65,8 +66,8 @@ class ViewsForm extends DependencySerialization implements FormInterface, Contai
   /**
    * Constructs a ViewsForm object.
    *
-   * @param \Drupal\Core\Controller\ControllerResolverInterface $controller_resolver
-   *   The controller resolver to get the subform form objects.
+   * @param \Drupal\Core\DependencyInjection\ClassResolverInterface $controller_resolver
+   *   The class resolver to get the subform form objects.
    * @param \Drupal\Core\Routing\UrlGeneratorInterface $url_generator
    *   The url generator to generate the form action.
    * @param \Symfony\Component\HttpFoundation\Request $request
@@ -76,8 +77,8 @@ class ViewsForm extends DependencySerialization implements FormInterface, Contai
    * @param string $view_display_id
    *   The ID of the active view's display.
    */
-  public function __construct(ControllerResolverInterface $controller_resolver, UrlGeneratorInterface $url_generator, Request $request, $view_id, $view_display_id) {
-    $this->controllerResolver = $controller_resolver;
+  public function __construct(ClassResolverInterface $controller_resolver, UrlGeneratorInterface $url_generator, Request $request, $view_id, $view_display_id) {
+    $this->classResolver = $controller_resolver;
     $this->urlGenerator = $url_generator;
     $this->request = $request;
     $this->viewId = $view_id;
@@ -169,17 +170,7 @@ class ViewsForm extends DependencySerialization implements FormInterface, Contai
   protected function getFormObject(array $form_state) {
     // If this is a class, instantiate it.
     $form_step_class = isset($form_state['step_controller'][$form_state['step']]) ? $form_state['step_controller'][$form_state['step']] : 'Drupal\views\Form\ViewsFormMainForm';
-    $container = \Drupal::getContainer();
-    if (class_exists($form_step_class)) {
-      if (in_array('Drupal\Core\DependencyInjection\ContainerInjectionInterface', class_implements($form_step_class))) {
-        return $form_step_class::create($container);
-      }
-
-      return new $form_step_class();
-    }
-
-    // Otherwise, it is a service.
-    return $container->get($form_step_class);
+    return $this->classResolver->getInstanceFromDefinition($form_step_class);
   }
 
 }
diff --git a/core/modules/views/views.theme.inc b/core/modules/views/views.theme.inc
index ae967bd..86e3e85 100644
--- a/core/modules/views/views.theme.inc
+++ b/core/modules/views/views.theme.inc
@@ -121,7 +121,7 @@ function template_preprocess_views_view(&$variables) {
     }
 
     $container = \Drupal::getContainer();
-    $form_object = new ViewsForm($container->get('controller_resolver'), $container->get('url_generator'), $container->get('request'), $view->storage->id(), $view->current_display);
+    $form_object = new ViewsForm($container->get('class_resolver'), $container->get('url_generator'), $container->get('request'), $view->storage->id(), $view->current_display);
     $form = \Drupal::formBuilder()->getForm($form_object, $view, $output);
     // The form is requesting that all non-essential views elements be hidden,
     // usually because the rendered step is not a view result.
diff --git a/core/tests/Drupal/Tests/Core/Controller/ControllerResolverTest.php b/core/tests/Drupal/Tests/Core/Controller/ControllerResolverTest.php
index da201f5..923c94b 100644
--- a/core/tests/Drupal/Tests/Core/Controller/ControllerResolverTest.php
+++ b/core/tests/Drupal/Tests/Core/Controller/ControllerResolverTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\Tests\Core\Controller;
 
 use Drupal\Core\Controller\ControllerResolver;
+use Drupal\Core\DependencyInjection\ClassResolver;
 use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Tests\UnitTestCase;
@@ -59,8 +60,9 @@ class ControllerResolverTest extends UnitTestCase {
     parent::setUp();
 
     $this->container = new ContainerBuilder();
-    $this->controllerResolver = new ControllerResolver();
-    $this->controllerResolver->setContainer($this->container);
+    $class_resolver = new ClassResolver();
+    $class_resolver->setContainer($this->container);
+    $this->controllerResolver = new ControllerResolver($class_resolver);
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityManagerTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityManagerTest.php
index 0056594..677eb18 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityManagerTest.php
@@ -81,6 +81,20 @@ class EntityManagerTest extends UnitTestCase {
   protected $translationManager;
 
   /**
+   * The form builder.
+   *
+   * @var \Drupal\Core\Form\FormBuilderInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $formBuilder;
+
+  /**
+   * The controller resolver.
+   *
+   * @var \Drupal\Core\Controller\ControllerResolverInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $controllerResolver;
+
+  /**
    * {@inheritdoc}
    */
   public static function getInfo() {
@@ -115,6 +129,9 @@ class EntityManagerTest extends UnitTestCase {
 
     $this->translationManager = $this->getStringTranslationStub();
 
+    $this->formBuilder = $this->getMock('Drupal\Core\Form\FormBuilderInterface');
+    $this->controllerResolver = $this->getClassResolverStub();
+
     $this->container = $this->getContainerWithCacheBins($this->cache);
 
     $this->discovery = $this->getMock('Drupal\Component\Plugin\Discovery\DiscoveryInterface');
@@ -148,7 +165,7 @@ class EntityManagerTest extends UnitTestCase {
       ->method('getDefinitions')
       ->will($this->returnValue($definitions));
 
-    $this->entityManager = new TestEntityManager(new \ArrayObject(), $this->moduleHandler, $this->cache, $this->languageManager, $this->translationManager);
+    $this->entityManager = new TestEntityManager(new \ArrayObject(), $this->moduleHandler, $this->cache, $this->languageManager, $this->translationManager, $this->getClassResolverStub());
     $this->entityManager->setContainer($this->container);
     $this->entityManager->setDiscovery($this->discovery);
   }
diff --git a/core/tests/Drupal/Tests/Core/Form/FormTestBase.php b/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
index 280e54e..640ce98 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
@@ -42,42 +42,49 @@ abstract class FormTestBase extends UnitTestCase {
   /**
    * The mocked URL generator.
    *
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\Routing\UrlGeneratorInterface
+   * @var \Drupal\Core\Routing\UrlGeneratorInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $urlGenerator;
 
   /**
    * The mocked module handler.
    *
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\Extension\ModuleHandlerInterface
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $moduleHandler;
 
   /**
    * The expirable key value store used by form cache.
    *
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface
+   * @var \Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $formCache;
 
   /**
    * The expirable key value store used by form state cache.
    *
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface
+   * @var \Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $formStateCache;
 
   /**
    * The current user.
    *
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\Session\AccountInterface
+   * @var \Drupal\Core\Session\AccountInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $account;
 
   /**
+   * The controller resolver.
+   *
+   * @var \Drupal\Core\Controller\ControllerResolverInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $controllerResolver;
+
+  /**
    * The CSRF token generator.
    *
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\Access\CsrfTokenGenerator
+   * @var \Drupal\Core\Access\CsrfTokenGenerator|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $csrfToken;
 
@@ -96,21 +103,33 @@ abstract class FormTestBase extends UnitTestCase {
   protected $requestStack;
 
   /**
+   * The class results.
+   *
+   * @var \Drupal\Core\DependencyInjection\ClassResolverInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $classResolver;
+
+  /**
    * The event dispatcher.
    *
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Symfony\Component\EventDispatcher\EventDispatcherInterface
+   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $eventDispatcher;
 
   /**
    * The expirable key value factory.
    *
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\KeyValueStore\KeyValueExpirableFactory
+   * @var \Drupal\Core\KeyValueStore\KeyValueExpirableFactory|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $keyValueExpirableFactory;
 
   /**
-   * @var \PHPUnit_Framework_MockObject_MockObject|\Drupal\Core\HttpKernel
+   * @var \Drupal\Core\StringTranslation\TranslationInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $translationManager;
+
+  /**
+   * @var \Drupal\Core\HttpKernel|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $httpKernel;
 
@@ -130,6 +149,7 @@ abstract class FormTestBase extends UnitTestCase {
       )));
 
     $this->urlGenerator = $this->getMock('Drupal\Core\Routing\UrlGeneratorInterface');
+    $this->classResolver = $this->getClassResolverStub();
     $this->csrfToken = $this->getMockBuilder('Drupal\Core\Access\CsrfTokenGenerator')
       ->disableOriginalConstructor()
       ->getMock();
@@ -150,7 +170,7 @@ abstract class FormTestBase extends UnitTestCase {
       ->setMethods(array('batchGet', 'drupalInstallationAttempted'))
       ->getMock();
 
-    $this->formBuilder = new TestFormBuilder($this->formValidator, $this->formSubmitter, $this->moduleHandler, $this->keyValueExpirableFactory, $this->eventDispatcher, $this->requestStack, $this->csrfToken, $this->httpKernel);
+    $this->formBuilder = new TestFormBuilder($this->formValidator, $this->formSubmitter, $this->moduleHandler, $this->keyValueExpirableFactory, $this->eventDispatcher, $this->requestStack, $this->classResolver, $this->csrfToken, $this->httpKernel);
     $this->formBuilder->setCurrentUser($this->account);
   }
 
diff --git a/core/tests/Drupal/Tests/Core/HttpKernelTest.php b/core/tests/Drupal/Tests/Core/HttpKernelTest.php
index bf712ec..8115ada 100644
--- a/core/tests/Drupal/Tests/Core/HttpKernelTest.php
+++ b/core/tests/Drupal/Tests/Core/HttpKernelTest.php
@@ -8,6 +8,7 @@
 namespace Drupal\Tests\Core;
 
 use Drupal\Core\Controller\ControllerResolver;
+use Drupal\Core\DependencyInjection\ClassResolver;
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\HttpKernel;
 use Drupal\Tests\UnitTestCase;
@@ -46,8 +47,9 @@ class HttpKernelTest extends UnitTestCase {
     $container->set('request', $request, 'request');
 
     $dispatcher = new EventDispatcher();
-    $controller_resolver = new ControllerResolver();
-    $controller_resolver->setContainer($container);
+    $class_resolver = new ClassResolver();
+    $class_resolver->setContainer($container);
+    $controller_resolver = new ControllerResolver($class_resolver);
 
     $http_kernel = new HttpKernel($dispatcher, $controller_resolver);
     $http_kernel->setContainer($container);
diff --git a/core/tests/Drupal/Tests/UnitTestCase.php b/core/tests/Drupal/Tests/UnitTestCase.php
index 898f40e..bcefce7 100644
--- a/core/tests/Drupal/Tests/UnitTestCase.php
+++ b/core/tests/Drupal/Tests/UnitTestCase.php
@@ -230,4 +230,25 @@ abstract class UnitTestCase extends \PHPUnit_Framework_TestCase {
     return $container;
   }
 
+  /**
+   * Returns a stub class resolver.
+   *
+   * @return \Drupal\Core\DependencyInjection\ClassResolverInterface|\PHPUnit_Framework_MockObject_MockObject
+   *   The class resolver stub.
+   */
+  protected function getClassResolverStub() {
+    $class_resolver = $this->getMock('Drupal\Core\DependencyInjection\ClassResolverInterface');
+    $class_resolver->expects($this->any())
+      ->method('getInstanceFromDefinition')
+      ->will($this->returnCallback(function ($class) {
+        if (is_subclass_of($class, 'Drupal\Core\DependencyInjection\ContainerInjectionInterface')) {
+          return $class::create(\Drupal::getContainer());
+        }
+        else {
+          return new $class();
+        }
+      }));
+    return $class_resolver;
+  }
+
 }