only in patch2:
unchanged:
--- a/core/modules/aggregator/src/Controller/AggregatorController.php
+++ b/core/modules/aggregator/src/Controller/AggregatorController.php
@@ -51,7 +51,7 @@ public static function create(ContainerInterface $container) {
    * Presents the aggregator feed creation form.
    *
    * @return array
-   *   A form array as expected by drupal_render().
+   *   A form array as expected by $renderer->render().
    */
   public function feedAdd() {
     $feed = $this->entityManager()->getStorage('aggregator_feed')
@@ -111,7 +111,7 @@ public function feedRefresh(FeedInterface $aggregator_feed) {
    * Displays the aggregator administration page.
    *
    * @return array
-   *   A render array as expected by drupal_render().
+   *   A render array as expected by $renderer->render().
    */
   public function adminOverview() {
     $entity_manager = $this->entityManager();
only in patch2:
unchanged:
--- a/core/modules/aggregator/src/Plugin/views/row/Rss.php
+++ b/core/modules/aggregator/src/Plugin/views/row/Rss.php
@@ -79,7 +79,7 @@ public function render($row) {
       '#options' => $this->options,
       '#row' => $item,
     );
-    return drupal_render_root($build);
+    return $this->renderer->renderRoot($build);
   }
 
 }