diff --git a/core/lib/Drupal/Core/Entity/HtmlEntityFormController.php b/core/lib/Drupal/Core/Entity/HtmlEntityFormController.php
index 8f62a40..41133e8 100644
--- a/core/lib/Drupal/Core/Entity/HtmlEntityFormController.php
+++ b/core/lib/Drupal/Core/Entity/HtmlEntityFormController.php
@@ -21,7 +21,7 @@ class HtmlEntityFormController extends HtmlFormController {
    * Due to reflection, the argument must be named $_entity_form. The parent
    * method has $request and $_form, but the parameter must match the route.
    */
-  public function content(Request $request, $_entity_form) {
+  public function content(Request $request, $_entity_form, $_values = FALSE) {
     return parent::content($request, $_entity_form);
   }
 
@@ -56,7 +56,25 @@ protected function getFormObject(Request $request, $form_arg) {
       $entity = $request->attributes->get($entity_type);
     }
     else {
-      $entity = $manager->getStorageController($entity_type)->create(array());
+      $values = array();
+      // A default values callback has been provided and the callable is in
+      // class::method format.
+      if (($_values = $request->attributes->get('_values')) && strpos($_values, '::') !== FALSE) {
+        // Extract the class and method from the given string.
+        list($class, $method) = explode('::', $_values);
+        // The default values callback is in a ControllerInterface object.
+        if (in_array('Drupal\Core\ControllerInterface', class_implements($class))) {
+          $defaults_class = $class::create($this->container);
+        }
+        else {
+          $defaults_class = new $class();
+        }
+
+        // Use _values callable to build default values for the entity.
+        $values = call_user_func(array($defaults_class, $method), $request);
+      }
+
+      $entity = $manager->getStorageController($entity_type)->create($values);
     }
 
     return $manager->getFormController($entity_type, $operation)->setEntity($entity);
diff --git a/core/modules/block/custom_block/custom_block.module b/core/modules/block/custom_block/custom_block.module
index b8785de..7fc46e0 100644
--- a/core/modules/block/custom_block/custom_block.module
+++ b/core/modules/block/custom_block/custom_block.module
@@ -73,13 +73,9 @@ function custom_block_menu() {
     'route_name' => 'custom_block_add_page',
   );
   $items['block/add/%custom_block_type'] = array(
-    'title callback' => 'entity_page_label',
-    'title arguments' => array(2),
-    'page callback' => 'custom_block_add',
-    'page arguments' => array(2),
-    'access arguments' => array('administer blocks'),
+    'title' => 'Add custom block',
     'description' => 'Add custom block',
-    'file' => 'custom_block.pages.inc',
+    'route_name' => 'custom_block_add_form'
   );
   // There has to be a base-item in order for contextual links to work.
   $items['block/%custom_block'] = array(
diff --git a/core/modules/block/custom_block/custom_block.pages.inc b/core/modules/block/custom_block/custom_block.pages.inc
index 9c802c4..7b7d4b4 100644
--- a/core/modules/block/custom_block/custom_block.pages.inc
+++ b/core/modules/block/custom_block/custom_block.pages.inc
@@ -35,36 +35,6 @@ function theme_custom_block_add_list($variables) {
   return $output;
 }
 
-
-/**
- * Page callback: Presents the custom block creation form.
- *
- * @param Drupal\custom_block\Plugin\Core\Entity\CustomBlockType $block_type
- *   The custom block type to add.
- *
- * @return array
- *   A form array as expected by drupal_render().
- *
- * @see custom_block_menu()
- */
-function custom_block_add(CustomBlockType $block_type) {
-  drupal_set_title(t('Add %type custom block', array(
-    '%type' => $block_type->label()
-  )), PASS_THROUGH);
-  $block = entity_create('custom_block', array(
-    'type' => $block_type->id()
-  ));
-  $options = array();
-  $request = drupal_container()->get('request');
-  if (($theme = $request->attributes->get('theme')) && in_array($theme, array_keys(list_themes()))) {
-    // We have navigated to this page from the block library and will keep track
-    // of the theme for redirecting the user to the configuration page for the
-    // newly created block in the given theme.
-    $block->setTheme($theme);
-  }
-  return entity_get_form($block);
-}
-
 /**
  * Page callback: Presents the custom block edit form.
  *
diff --git a/core/modules/block/custom_block/custom_block.routing.yml b/core/modules/block/custom_block/custom_block.routing.yml
index ac4ec99..5a94841 100644
--- a/core/modules/block/custom_block/custom_block.routing.yml
+++ b/core/modules/block/custom_block/custom_block.routing.yml
@@ -12,3 +12,10 @@ custom_block_add_page:
     _content: 'Drupal\custom_block\Controller\CustomBlockController::add'
   requirements:
     _permission: 'administer blocks'
+custom_block_add_form:
+  pattern: 'block/add/{custom_block_type}'
+  defaults:
+    _entity_form: 'custom_block.default'
+    _values: 'Drupal\custom_block\Controller\CustomBlockController::defaults'
+  requirements:
+    _permission: 'administer blocks'
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Controller/CustomBlockController.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Controller/CustomBlockController.php
index 783ef84..e8c04f0 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Controller/CustomBlockController.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Controller/CustomBlockController.php
@@ -9,7 +9,7 @@
 
 use Drupal\Core\ControllerInterface;
 use Drupal\Core\Entity\EntityManager;
-use Drupal\Core\Extension\ModuleHandler;
+use Drupal\custom_block\CustomBlockTypeInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
 
@@ -30,20 +30,12 @@ class CustomBlockController implements ControllerInterface {
   protected $entityManager;
 
   /**
-   * Module handler service.
-   *
-   * @var \Drupal\Core\Extension\ModuleHandler
-   */
-  protected $moduleHandler;
-
-  /**
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container) {
     return new static(
       $container->get('request'),
-      $container->get('plugin.manager.entity'),
-      $container->get('module_handler')
+      $container->get('plugin.manager.entity')
     );
   }
 
@@ -54,13 +46,10 @@ public static function create(ContainerInterface $container) {
    *   Current request.
    * @param \Drupal\Core\Entity\EntityManager $entity_manager
    *   Entity manager service.
-   * @param \Drupal\Core\Extension\ModuleHandler $module_handler
-   *   Module Handler service.
    */
-  public function __construct(Request $request, EntityManager $entity_manager, ModuleHandler $module_handler) {
+  public function __construct(Request $request, EntityManager $entity_manager) {
     $this->request = $request;
     $this->entityManager = $entity_manager;
-    $this->moduleHandler = $module_handler;
   }
 
   /**
@@ -84,13 +73,37 @@ public function add() {
     $types = $this->entityManager->getStorageController('custom_block_type')->load();
     if ($types && count($types) == 1) {
       $type = reset($types);
-      // @todo convert this to OO once block/add/%type uses a Controller. Will
-      //   be fixed in http://drupal.org/node/1978166.
-      $this->moduleHandler->loadInclude('custom_block', 'pages.inc');
-      return custom_block_add($type);
+      $block = $this->entityManager->getStorageController('custom_block')->create(array(
+        'type' => $custom_block_type->id()
+      ));
+      $options = array();
+      if (($theme = $this->request->attributes->get('theme')) && in_array($theme, array_keys(list_themes()))) {
+        // We have navigated to this page from the block library and will keep track
+        // of the theme for redirecting the user to the configuration page for the
+        // newly created block in the given theme.
+        $block->setTheme($theme);
+      }
+      // @todo remove call to entity_get_form() when
+      //  http://drupal.org/node/1982980 is in.
+      return entity_get_form($block);
     }
 
     return array('#theme' => 'custom_block_add_list', '#content' => $types);
   }
 
+  /**
+   * Returns default values for the new entity.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The current request.
+   *
+   * @return array
+   *   Array of default values to use whilst creating entity form.
+   */
+  public function defaults(Request $request) {
+    $custom_block_type = $request->attributes->get('custom_block_type');
+    return array(
+      'type' => $custom_block_type->id()
+    );
+  }
 }
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockFormController.php b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockFormController.php
index 1a09dbf..96b87e7 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockFormController.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockFormController.php
@@ -42,6 +42,14 @@ protected function prepareEntity() {
    */
   public function form(array $form, array &$form_state) {
     $block = $this->entity;
+
+    // @todo Remove this when https://drupal.org/node/1981644 is in.
+    if ($block->isNew()) {
+      drupal_set_title(t('Add %type custom block', array(
+        '%type' => $block->bundle()
+      )), PASS_THROUGH);
+    }
+
     // Override the default CSS class name, since the user-defined custom block
     // type name in 'TYPE-block-form' potentially clashes with third-party class
     // names.