diff --git a/core/modules/aggregator/lib/Drupal/aggregator/FeedFormController.php b/core/modules/aggregator/lib/Drupal/aggregator/FeedFormController.php
index ab27c45..6231e0a 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/FeedFormController.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/FeedFormController.php
@@ -24,7 +24,7 @@ class FeedFormController extends EntityFormControllerNG {
    *
    * @var \Drupal\Core\Entity\EntityStorageControllerInterface
    */
-  protected $feedStorage;
+  protected $feedStorageController;
 
   /**
    * The category storage controller.
@@ -42,7 +42,7 @@ class FeedFormController extends EntityFormControllerNG {
    *   The category storage controller.
    */
   public function __construct(EntityStorageControllerInterface $feed_storage, CategoryStorageControllerInterface $category_storage_controller) {
-    $this->feedStorage = $feed_storage;
+    $this->feedStorageController = $feed_storage;
     $this->categoryStorageController = $category_storage_controller;
   }
 
@@ -125,7 +125,7 @@ public function form(array $form, array &$form_state) {
   public function validate(array $form, array &$form_state) {
     $feed = $this->buildEntity($form, $form_state);
     // Check for duplicate titles.
-    $result = $this->feedStorage->getFeedDuplicates($feed);
+    $result = $this->feedStorageController->getFeedDuplicates($feed);
     foreach ($result as $item) {
       if (strcasecmp($item->title, $feed->label()) == 0) {
         form_set_error('title', $this->t('A feed named %feed already exists. Enter a unique title.', array('%feed' => $feed->label())));
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php b/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
index 1ff529f..e0fc1a0 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageController.php
@@ -7,8 +7,8 @@
 
 namespace Drupal\aggregator;
 
+use Drupal\aggregator\FeedInterface;
 use Drupal\Core\Entity\DatabaseStorageControllerNG;
-use Drupal\Core\Entity\EntityInterface;
 
 /**
  * Controller class for aggregator's feeds.
@@ -38,7 +38,7 @@ public function loadCategories(array $feeds) {
   /**
    * {@inheritdoc}
    */
-  public function saveCategories(EntityInterface $feed, array $categories) {
+  public function saveCategories(FeedInterface $feed, array $categories) {
     foreach ($categories as $cid => $value) {
       if ($value) {
         $this->database->insert('aggregator_category_feed')
@@ -64,7 +64,7 @@ public function deleteCategories(array $feeds) {
   /**
    * {@inheritdoc}
    */
-  public function getFeedDuplicates(EntityInterface $feed) {
+  public function getFeedDuplicates(FeedInterface $feed) {
     if ($feed->id()) {
       $query = $this->database->query("SELECT title, url FROM {aggregator_feed} WHERE (title = :title OR url = :url) AND fid <> :fid", array(':title' => $feed->label(), ':url' => $feed->url->value, ':fid' => $feed->id()));
     }
@@ -72,7 +72,7 @@ public function getFeedDuplicates(EntityInterface $feed) {
       $query = $this->database->query("SELECT title, url FROM {aggregator_feed} WHERE title = :title OR url = :url", array(':title' => $feed->label(), ':url' => $feed->url->value));
     }
 
-    return $query;
+    return $query->fetchAll();
   }
 
 }
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageControllerInterface.php b/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageControllerInterface.php
index cd8162c..ab33938 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageControllerInterface.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/FeedStorageControllerInterface.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\aggregator;
 
-use Drupal\Core\Entity\EntityInterface;
+use Drupal\aggregator\FeedInterface;
 use Drupal\Core\Entity\EntityStorageControllerInterface;
 
 /**
@@ -27,12 +27,12 @@ public function loadCategories(array $feeds);
   /**
    * Saves the categories of a feed.
    *
-   * @param \Drupal\Core\Entity\EntityInterface $feed
+   * @param \Drupal\aggregator\Entity\FeedInterface $feed
    *   The feed entity.
    * @param array $categories
    *   The array of categories.
    */
-  public function saveCategories(EntityInterface $feed, array $categories);
+  public function saveCategories(FeedInterface $feed, array $categories);
 
   /**
    * Deletes the categories of a feed.
@@ -45,8 +45,12 @@ public function deleteCategories(array $feeds);
   /**
    * Provides a list of duplicate feeds.
    *
-   * @param \Drupal\Core\Entity\EntityInterface $feed
+   * @param \Drupal\aggregator\Entity\FeedInterface $feed
    *   The feed entity.
+   *
+   * @return
+   *   An array with the list of duplicated feeds.
    */
-  public function getFeedDuplicates(EntityInterface $feed);
+  public function getFeedDuplicates(FeedInterface $feed);
+
 }
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php b/core/modules/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php
index 8eee427..e2cb778 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php
@@ -10,7 +10,6 @@
 use Drupal\aggregator\CategoryStorageControllerInterface;
 use Drupal\aggregator\FeedStorageControllerInterface;
 use Drupal\Component\Utility\Url;
-use Drupal\Core\Database\Connection;
 use Drupal\Core\Entity\Query\QueryFactory;
 use Drupal\Core\Form\FormBase;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -24,13 +23,6 @@
 class OpmlFeedAdd extends FormBase {
 
   /**
-   * The database connection object.
-   *
-   * @var \Drupal\Core\Database\Connection
-   */
-  protected $database;
-
-  /**
    * The entity query factory object.
    *
    * @var \Drupal\Core\Entity\Query\QueryFactory
@@ -42,7 +34,7 @@ class OpmlFeedAdd extends FormBase {
    *
    * @var \Drupal\aggregator\FeedStorageControllerInterface
    */
-  protected $feedStorage;
+  protected $feedStorageController;
 
   /**
    * The HTTP client to fetch the feed data with.
@@ -61,8 +53,6 @@ class OpmlFeedAdd extends FormBase {
   /**
    * Constructs a database object.
    *
-   * @param \Drupal\Core\Database\Connection $database
-   *   The database object.
    * @param \Drupal\Core\Entity\Query\QueryFactory $query_factory
    *   The entity query object.
    * @param \Drupal\aggregator\FeedStorageControllerInterface $feed_storage
@@ -72,10 +62,9 @@ class OpmlFeedAdd extends FormBase {
    * @param \Drupal\aggregator\CategoryStorageControllerInterface $category_storage_controller
    *   The category storage controller.
    */
-  public function __construct(Connection $database, QueryFactory $query_factory, FeedStorageControllerInterface $feed_storage, ClientInterface $http_client, CategoryStorageControllerInterface $category_storage_controller) {
-    $this->database = $database;
+  public function __construct(QueryFactory $query_factory, FeedStorageControllerInterface $feed_storage, ClientInterface $http_client, CategoryStorageControllerInterface $category_storage_controller) {
     $this->queryFactory = $query_factory;
-    $this->feedStorage = $feed_storage;
+    $this->feedStorageController = $feed_storage;
     $this->httpClient = $http_client;
     $this->categoryStorageController = $category_storage_controller;
   }
@@ -85,7 +74,6 @@ public function __construct(Connection $database, QueryFactory $query_factory, F
    */
   public static function create(ContainerInterface $container) {
     return new static(
-      $container->get('database'),
       $container->get('entity.query'),
       $container->get('entity.manager')->getStorageController('aggregator_feed'),
       $container->get('http_default_client'),
@@ -204,7 +192,7 @@ public function submitForm(array &$form, array &$form_state) {
       $ids = $query
         ->condition($condition)
         ->execute();
-      $result = $this->feedStorage->loadMultiple($ids);
+      $result = $this->feedStorageController->loadMultiple($ids);
       foreach ($result as $old) {
         if (strcasecmp($old->label(), $feed['title']) == 0) {
           drupal_set_message($this->t('A feed named %title already exists.', array('%title' => $old->label())), 'warning');
@@ -216,7 +204,7 @@ public function submitForm(array &$form, array &$form_state) {
         }
       }
 
-      $new_feed = $this->feedStorage->create(array(
+      $new_feed = $this->feedStorageController->create(array(
         'title' => $feed['title'],
         'url' => $feed['url'],
         'refresh' => $form_state['values']['refresh'],