diff --git a/core/includes/common.inc b/core/includes/common.inc
index 5fd753d..93d52fa 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -631,13 +631,7 @@ function drupal_process_attached(array $elements) {
           // @todo Remove validation in https://www.drupal.org/node/2477223
           break;
         case 'feed':
-          $args = [[
-            'href' => $args[0],
-            'rel' => 'alternate',
-            'title' => $args[1],
-            'type' => 'application/rss+xml',
-          ]];
-          call_user_func_array('_drupal_add_html_head_link', $args);
+          // @todo Remove validation in https://www.drupal.org/node/2477223
           break;
         case 'html_head_link':
           // @todo Remove validation in https://www.drupal.org/node/2477223
diff --git a/core/lib/Drupal/Core/Render/HtmlResponseAttachmentsProcessor.php b/core/lib/Drupal/Core/Render/HtmlResponseAttachmentsProcessor.php
index 2c57845..5841ea4 100644
--- a/core/lib/Drupal/Core/Render/HtmlResponseAttachmentsProcessor.php
+++ b/core/lib/Drupal/Core/Render/HtmlResponseAttachmentsProcessor.php
@@ -11,6 +11,7 @@
 use Drupal\Core\Asset\AttachedAssets;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Component\Utility\SafeMarkup;
 use Symfony\Component\HttpFoundation\RequestStack;
 
 /**
@@ -118,21 +119,36 @@ public function processAttachments(AttachmentsInterface $response) {
 
     $variables = $this->processAssetLibraries($attached, $placeholders);
 
-    // If there is a 'head' placeholder, then we can process html_head and
-    // html_head_link.
-    if (isset($placeholders['head'])) {
+    // Since we can only replace content in the HTML head section if there's a
+    // placeholder for it, we can safely avoid processing the render array if
+    // it's not present.
+    if (!empty($placeholders['head'])) {
+
+      // feed is a special casse of html_head_link.
+      if (!empty($attached['feed'])) {
+        $feed = $attached['feed'];
+        $feed_link = [
+          'href' => $feed[0],
+          'rel' => 'alternate',
+          'title' => $feed[1],
+          'type' => 'application/rss+xml',
+        ];
+        $attached['html_head_link'][] = $feed_link;
+      }
+
       // html_head_link is a special case of html_head which can be present as
       // a head element, but also as a Link: http header depending on settings
       // in the render array. Processing it can add to both the html_head and
-      // http_header sections, so we must address it first.
-      if (isset($attached['html_head_link'])) {
+      // http_header keys of #attached, so we must address it first.
+      if (!empty($attached['html_head_link'])) {
         $link_attached = $this->processHtmlHeadLink($attached['html_head_link']);
         // Merge $link_attached so that its html_head and http_header
         // sections are present for further processing.
         $attached = array_merge($attached, $link_attached);
       }
+
       // Now we can process html_head.
-      if (isset($attached['html_head'])) {
+      if (!empty($attached['html_head'])) {
         $head = $this->processHtmlHead($attached['html_head']);
         // Invoke hook_html_head_alter().
         $this->moduleHandler->alter('html_head', $head);
@@ -140,19 +156,10 @@ public function processAttachments(AttachmentsInterface $response) {
       }
     }
 
-    // Some elements are still handled by drupal_process_attached().
-    $all_attached = ['#attached' => $attached];
-    drupal_process_attached($all_attached);
-    // We have to get these elements back from the legacy system using
-    // drupal_get_html_head().
-    if (isset($placeholders['head'])) {
-      $variables['head'] = array_merge($variables['head'], drupal_get_html_head(FALSE));
-    }
-
     // Now replace the placeholders in the response content with the real data.
     $this->renderPlaceholders($response, $placeholders, $variables);
 
-    // Finally set the headers on the response if any bubbled.
+    // Set the HTTP headers on the response if any bubbled.
     if (!empty($attached['http_header'])) {
       $this->setHeaders($response, $attached['http_header']);
     }
@@ -278,12 +285,12 @@ protected function processHtmlHead(array $html_head) {
    * Transform a html_head_link array into html_head and http_header arrays.
    *
    * html_head_link is a special case of html_head which can be present as
-   * a head element, but also as a Link: http header depending on settings
-   * in the render array. Processing it can add to both the html_head and
-   * http_header sections.
+   * a link item in the HTML head section, and also as a Link: HTTP header,
+   * depending on options in the render array. Processing it can add to both the
+   * html_head and http_header sections.
    *
    * @param array $html_head_link
-   *   The 'html_head_link' section of a render array.
+   *   The 'html_head_link' value of a render array.
    *
    * @return array
    *   An ['#attached'] section of a render array. This allows us to easily
@@ -298,6 +305,7 @@ protected function processHtmlHeadLink(array $html_head_link) {
     foreach ($html_head_link as $item) {
       $attributes = $item[0];
       $should_add_header = isset($item[1]) ? $item[1] : FALSE;
+
       $element = array(
         '#tag' => 'link',
         '#attributes' => $attributes,
@@ -311,9 +319,8 @@ protected function processHtmlHeadLink(array $html_head_link) {
         unset($attributes['href']);
         $attached['http_header'][] = ['Link', $href . drupal_http_header_attributes($attributes), TRUE];
       }
-
-      return $attached;
     }
+    return $attached;
   }
 
 }