diff --git a/core/authorize.php b/core/authorize.php
index 35277f6..d5baed4 100644
--- a/core/authorize.php
+++ b/core/authorize.php
@@ -20,11 +20,11 @@
  * @link authorize Authorized operation helper functions @endlink
  */
 
+use Drupal\Core\Render\CacheableHtmlResponse;
 use Drupal\Core\DrupalKernel;
 use Drupal\Core\Url;
 use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpFoundation\Response;
 use Drupal\Core\Site\Settings;
 
 // Change the directory to the Drupal root.
@@ -85,7 +85,7 @@ function authorize_access_allowed(Request $request) {
 $content = [];
 $show_messages = TRUE;
 
-$response = new Response();
+$response = new CacheableHtmlResponse();
 if (authorize_access_allowed($request)) {
   // Load both the Form API and Batch API.
   require_once __DIR__ . '/includes/form.inc';
@@ -159,9 +159,15 @@ function authorize_access_allowed(Request $request) {
 }
 
 if (!empty($content)) {
+  $bare_html_page_renderer = \Drupal::service('bare_html_page_renderer');
   $response->headers->set('Content-Type', 'text/html; charset=utf-8');
-  $response->setContent(\Drupal::service('bare_html_page_renderer')->renderBarePage($content, $page_title, 'maintenance_page', array(
+  $response->setContent($bare_html_page_renderer->renderBarePage($content, $page_title, 'maintenance_page', array(
     '#show_messages' => $show_messages,
   )));
+
+  // Filter the response as it does not go via the usual chain,
+  // but there are assets on there that need to be rendered.
+  $bare_html_page_renderer->filterResponse($response);
+
   $response->send();
 }
diff --git a/core/core.services.yml b/core/core.services.yml
index 58db84c..84ecdca 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -897,7 +897,7 @@ services:
     arguments: ['@router', '@router.request_context', NULL, '@request_stack']
   bare_html_page_renderer:
     class: Drupal\Core\Render\BareHtmlPageRenderer
-    arguments: ['@renderer']
+    arguments: ['@renderer', '@render_cache']
     lazy: true
   private_key:
     class: Drupal\Core\PrivateKey
diff --git a/core/includes/batch.inc b/core/includes/batch.inc
index 7d905cd..a5d6242 100644
--- a/core/includes/batch.inc
+++ b/core/includes/batch.inc
@@ -135,9 +135,11 @@ function _batch_progress_page() {
     // additional HTML output by PHP shows up inside the page rather than below
     // it. While this causes invalid HTML, the same would be true if we didn't,
     // as content is not allowed to appear after </html> anyway.
-    $fallback = \Drupal::service('bare_html_page_renderer')->renderBarePage(['#markup' => $fallback], $current_set['title'], 'maintenance_page', array(
+    $bare_html_page_renderer = \Drupal::service('bare_html_page_renderer');
+    $content = $bare_html_page_renderer->renderBarePage(['#markup' => $fallback], $current_set['title'], 'maintenance_page', array(
       '#show_messages' => FALSE,
     ));
+    $fallback = $bare_html_page_renderer->filterRenderArray($content);
     list($fallback) = explode('<!--partial-->', $fallback);
     print $fallback;
 
diff --git a/core/includes/errors.inc b/core/includes/errors.inc
index 5e38a97..8caf68f 100644
--- a/core/includes/errors.inc
+++ b/core/includes/errors.inc
@@ -241,12 +241,18 @@ function _drupal_log_error($error, $fatal = FALSE) {
           '#markup' => $message,
         );
         install_display_output($output, $GLOBALS['install_state']);
+        exit;
       }
-      else {
-        $output = \Drupal::service('bare_html_page_renderer')->renderBarePage(['#markup' => $message], 'Error', 'maintenance_page');
-      }
 
-      $response = new Response($output, 500);
+      $bare_html_page_renderer = \Drupal::service('bare_html_page_renderer');
+      $output = $bare_html_page_renderer->renderBarePage(['#markup' => $message], 'Error', 'maintenance_page', TRUE);
+
+      $response = new CacheableHtmlResponse($output, 500);
+
+      // Filter the response as it does not go via the usual chain,
+      // but there are assets on there that need to be rendered.
+      $bare_html_page_renderer->filterResponse($response);
+
       $response->setStatusCode(500, '500 Service unavailable (with message)');
       // An exception must halt script execution.
       $response->send();
diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index d8f3136..0e7639e 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1311,41 +1311,11 @@ function template_preprocess_html(&$variables) {
   // @deprecated in Drupal 8.0.0, will be removed before Drupal 9.0.0.
   $variables['head_title_array'] = $head_title;
 
-  // Collect all attachments. This must happen in the preprocess function for
-  // #type => html, to ensure that attachments added in #pre_render callbacks
-  // for #type => html are included.
-  $attached = $variables['html']['#attached'];
-  $attached = drupal_merge_attached($attached, $variables['page']['#attached']);
-  if (isset($variables['page_top'])) {
-    $attached = drupal_merge_attached($attached, $variables['page_top']['#attached']);
-  }
-  if (isset($variables['page_bottom'])) {
-    $attached = drupal_merge_attached($attached, $variables['page_bottom']['#attached']);
-  }
-
-  // Render the attachments into HTML markup to be used directly in the template
-  // for #type => html: html.html.twig.
-  $all_attached = ['#attached' => $attached];
-  $assets = AttachedAssets::createFromRenderArray($all_attached);
-  // Take Ajax page state into account, to allow for something like Turbolinks
-  // to be implemented without altering core.
-  // @see https://github.com/rails/turbolinks/
-  $ajax_page_state = \Drupal::request()->request->get('ajax_page_state');
-  $assets->setAlreadyLoadedLibraries(isset($ajax_page_state) ? explode(',', $ajax_page_state['libraries']) : []);
-  // Optimize CSS/JS if necessary, but only during normal site operation.
-  $optimize_css = !defined('MAINTENANCE_MODE') && \Drupal::config('system.performance')->get('css.preprocess');
-  $optimize_js = !defined('MAINTENANCE_MODE') && \Drupal::config('system.performance')->get('js.preprocess');
-  // Render the asset collections.
-  $asset_resolver = \Drupal::service('asset.resolver');
-  $variables['styles'] = \Drupal::service('asset.css.collection_renderer')->render($asset_resolver->getCssAssets($assets, $optimize_css));
-  list($js_assets_header, $js_assets_footer) = $asset_resolver->getJsAssets($assets, $optimize_js);
-  $js_collection_renderer = \Drupal::service('asset.js.collection_renderer');
-  $variables['scripts'] = $js_collection_renderer->render($js_assets_header);
-  $variables['scripts_bottom'] = $js_collection_renderer->render($js_assets_footer);
-
-  // Handle all non-asset attachments.
-  drupal_process_attached($all_attached);
-  $variables['head'] = drupal_get_html_head(FALSE);
+  // @todo Move to a service.
+  $variables['styles']['#markup'] = '<!-- X-DRUPAL-STYLES-PLACEHOLDER -->';
+  $variables['scripts']['#markup'] = '<!-- X-DRUPAL-SCRIPTS-PLACEHOLDER -->';
+  $variables['scripts_bottom']['#markup'] = '<!-- X-DRUPAL-SCRIPTS-BOTTOM-PLACEHOLDER -->';
+  $variables['head']['#markup'] = '<!-- X-DRUPAL-HEAD-PLACEHOLDER -->';
 }
 
 /**
diff --git a/core/lib/Drupal/Core/Ajax/AjaxResponse.php b/core/lib/Drupal/Core/Ajax/AjaxResponse.php
index befb3be..c2d8d06 100644
--- a/core/lib/Drupal/Core/Ajax/AjaxResponse.php
+++ b/core/lib/Drupal/Core/Ajax/AjaxResponse.php
@@ -9,6 +9,8 @@
 
 use Drupal\Core\Asset\AttachedAssets;
 use Drupal\Core\Render\Renderer;
+use Drupal\Core\Render\AttachmentsResponseInterface;
+use Drupal\Core\Render\AttachmentsResponseTrait;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\JsonResponse;
 use Symfony\Component\HttpFoundation\Request;
@@ -19,7 +21,9 @@
  *
  * @ingroup ajax
  */
-class AjaxResponse extends JsonResponse {
+class AjaxResponse extends JsonResponse implements AttachmentsResponseInterface {
+
+  use AttachmentsResponseTrait;
 
   /**
    * The array of ajax commands.
@@ -29,32 +33,6 @@ class AjaxResponse extends JsonResponse {
   protected $commands = array();
 
   /**
-   * The attachments for this Ajax response.
-   *
-   * @var array
-   */
-  protected $attachments = [
-    'library' => [],
-    'drupalSettings' => [],
-  ];
-
-  /**
-   * Sets attachments for this Ajax response.
-   *
-   * When this Ajax response is rendered, it will take care of generating the
-   * necessary Ajax commands, if any.
-   *
-   * @param array $attachments
-   *   An #attached array.
-   *
-   * @return $this
-   */
-  public function setAttachments(array $attachments) {
-    $this->attachments = $attachments;
-    return $this;
-  }
-
-  /**
    * Add an AJAX command to the response.
    *
    * @param \Drupal\Core\Ajax\CommandInterface $command
@@ -79,7 +57,7 @@ public function addCommand(CommandInterface $command, $prepend = FALSE) {
         'library' => $assets->getLibraries(),
         'drupalSettings' => $assets->getSettings(),
       ];
-      $attachments = $this->getRenderer()->mergeAttachments($this->attachments, $attachments);
+      $attachments = $this->getRenderer()->mergeAttachments($this->getAttachments(), $attachments);
       $this->setAttachments($attachments);
     }
 
@@ -171,11 +149,13 @@ protected function ajaxRender(Request $request) {
     $optimize_css = !defined('MAINTENANCE_MODE') && $config->get('css.preprocess');
     $optimize_js = !defined('MAINTENANCE_MODE') && $config->get('js.preprocess');
 
+    $attachments = $this->getAttachments();
+
     // Resolve the attached libraries into asset collections.
     $assets = new AttachedAssets();
-    $assets->setLibraries(isset($this->attachments['library']) ? $this->attachments['library'] : [])
+    $assets->setLibraries(isset($attachments['library']) ? $attachments['library'] : [])
       ->setAlreadyLoadedLibraries(isset($ajax_page_state) ? explode(',', $ajax_page_state['libraries']) : [])
-      ->setSettings(isset($this->attachments['drupalSettings']) ? $this->attachments['drupalSettings'] : []);
+      ->setSettings(isset($attachments['drupalSettings']) ? $attachments['drupalSettings'] : []);
     $asset_resolver = \Drupal::service('asset.resolver');
     $css_assets = $asset_resolver->getCssAssets($assets, $optimize_css);
     list($js_assets_header, $js_assets_footer) = $asset_resolver->getJsAssets($assets, $optimize_js);
diff --git a/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionSubscriber.php
index 883927c..17a7315 100644
--- a/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionSubscriber.php
@@ -10,12 +10,12 @@
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Render\BareHtmlPageRendererInterface;
+use Drupal\Core\Render\CacheableHtmlResponse;
 use Drupal\Core\StringTranslation\StringTranslationTrait;
 use Drupal\Core\Utility\Error;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpFoundation\JsonResponse;
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
 use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
 use Symfony\Component\HttpKernel\KernelEvents;
@@ -130,7 +130,7 @@ protected function onHtml(GetResponseForExceptionEvent $event) {
 
     $content = $this->t('The website encountered an unexpected error. Please try again later.');
     $output = $this->bareHtmlPageRenderer->renderBarePage(['#markup' => $content], $this->t('Error'), 'maintenance_page');
-    $response = new Response($output);
+    $response = new CacheableHtmlResponse($output);
 
     if ($exception instanceof HttpExceptionInterface) {
       $response->setStatusCode($exception->getStatusCode());
diff --git a/core/lib/Drupal/Core/EventSubscriber/FinishResponseSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/FinishResponseSubscriber.php
index bee69a1..fdaeb25 100644
--- a/core/lib/Drupal/Core/EventSubscriber/FinishResponseSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/FinishResponseSubscriber.php
@@ -8,6 +8,8 @@
 namespace Drupal\Core\EventSubscriber;
 
 use Drupal\Component\Datetime\DateTimePlus;
+use Drupal\Core\Asset\AttachedAssets;
+use Drupal\Core\Ajax\AjaxResponse;
 use Drupal\Core\Cache\CacheableResponseInterface;
 use Drupal\Core\Cache\CacheContextsManager;
 use Drupal\Core\Config\Config;
@@ -15,6 +17,7 @@
 use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\Core\PageCache\RequestPolicyInterface;
 use Drupal\Core\PageCache\ResponsePolicyInterface;
+use Drupal\Core\Render\AttachmentsResponseInterface;
 use Drupal\Core\Site\Settings;
 use Symfony\Component\HttpFoundation\BinaryFileResponse;
 use Symfony\Component\HttpFoundation\Request;
@@ -114,14 +117,8 @@ public function onRespond(FilterResponseEvent $event) {
     // https://www.owasp.org/index.php/List_of_useful_HTTP_headers
     $response->headers->set('X-Content-Type-Options', 'nosniff', FALSE);
 
-    // Attach globally-declared headers to the response object so that Symfony
-    // can send them for us correctly.
-    // @todo Remove this once drupal_process_attached() no longer calls
-    //    _drupal_add_http_header(), which has its own static. Instead,
-    //    _drupal_process_attached() should use
-    //    \Symfony\Component\HttpFoundation\Response->headers->set(), which is
-    //    already documented on the (deprecated) _drupal_process_attached() to
-    //    become the final, intended mechanism.
+    static::processAttachments($response);
+
     $headers = drupal_get_http_header();
     foreach ($headers as $name => $value) {
       // Symfony special-cases the 'Status' header.
@@ -158,6 +155,54 @@ public function onRespond(FilterResponseEvent $event) {
     }
   }
 
+  public static function processAttachments($response) {
+    // @todo Move to a service.
+    if ($response instanceof AttachmentsResponseInterface && !($response instanceof AjaxResponse)) {
+      // Render the attachments into HTML markup
+      $attached = $response->getAttachments();
+      $all_attached = ['#attached' => $attached];
+
+      $assets = AttachedAssets::createFromRenderArray($all_attached);
+      // Take Ajax page state into account, to allow for something like Turbolinks
+      // to be implemented without altering core.
+      // @see https://github.com/rails/turbolinks/
+      $ajax_page_state = \Drupal::request()->request->get('ajax_page_state');
+      $assets->setAlreadyLoadedLibraries(isset($ajax_page_state) ? explode(',', $ajax_page_state['libraries']) : []);
+      // Optimize CSS/JS if necessary, but only during normal site operation.
+      $optimize_css = !defined('MAINTENANCE_MODE') && \Drupal::config('system.performance')->get('css.preprocess');
+      $optimize_js = !defined('MAINTENANCE_MODE') && \Drupal::config('system.performance')->get('js.preprocess');
+      // Render the asset collections.
+      $asset_resolver = \Drupal::service('asset.resolver');
+
+      $variables = [];
+      $variables['styles'] = \Drupal::service('asset.css.collection_renderer')->render($asset_resolver->getCssAssets($assets, $optimize_css));
+      list($js_assets_header, $js_assets_footer) = $asset_resolver->getJsAssets($assets, $optimize_js);
+      $js_collection_renderer = \Drupal::service('asset.js.collection_renderer');
+      $variables['scripts'] = $js_collection_renderer->render($js_assets_header);
+      $variables['scripts_bottom'] = $js_collection_renderer->render($js_assets_footer);
+
+      // Handle all non-asset attachments.
+      drupal_process_attached($all_attached);
+      $variables['head'] = drupal_get_html_head(FALSE);
+
+      $content = $response->getContent();
+
+      $map = [
+        'styles' => '<!-- X-DRUPAL-STYLES-PLACEHOLDER -->',
+        'scripts' => '<!-- X-DRUPAL-SCRIPTS-PLACEHOLDER -->',
+        'scripts_bottom' => '<!-- X-DRUPAL-SCRIPTS-BOTTOM-PLACEHOLDER -->',
+        'head' => '<!-- X-DRUPAL-HEAD-PLACEHOLDER -->',
+      ];
+      foreach ($map as $key => $placeholder) {
+        if (strpos($content, $placeholder) !== FALSE) {
+          $content = str_replace($placeholder, render($variables[$key]), $content);
+        }
+      }
+
+      $response->setContent($content);
+    }
+  }
+
   /**
    * Determine whether the given response has a custom Cache-Control header.
    *
diff --git a/core/lib/Drupal/Core/EventSubscriber/MaintenanceModeSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/MaintenanceModeSubscriber.php
index e43d00e..8adec60 100644
--- a/core/lib/Drupal/Core/EventSubscriber/MaintenanceModeSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/MaintenanceModeSubscriber.php
@@ -11,6 +11,7 @@
 use Drupal\Component\Utility\Xss;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Render\BareHtmlPageRendererInterface;
+use Drupal\Core\Render\CacheableHtmlResponse;
 use Drupal\Core\Routing\RouteMatch;
 use Drupal\Core\Routing\UrlGeneratorInterface;
 use Drupal\Core\Session\AccountInterface;
@@ -18,7 +19,6 @@
 use Drupal\Core\StringTranslation\StringTranslationTrait;
 use Drupal\Core\StringTranslation\TranslationInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
-use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Event\GetResponseEvent;
 use Symfony\Component\HttpKernel\KernelEvents;
 
@@ -108,7 +108,7 @@ public function onKernelRequestMaintenance(GetResponseEvent $event) {
           '@site' => $this->config->get('system.site')->get('name'),
         )));
         $output = $this->bareHtmlPageRenderer->renderBarePage(['#markup' => $content], $this->t('Site under maintenance'), 'maintenance_page');
-        $response = new Response($output, 503);
+        $response = new CacheableHtmlResponse($output, 503);
         $event->setResponse($response);
       }
       else {
diff --git a/core/lib/Drupal/Core/Render/AttachmentsResponseInterface.php b/core/lib/Drupal/Core/Render/AttachmentsResponseInterface.php
new file mode 100644
index 0000000..4c0b7b5
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/AttachmentsResponseInterface.php
@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Render\AttachmentsResponseInterface.
+ */
+
+namespace Drupal\Core\Render;
+
+/**
+ * Defines an interface for responses that can expose #attached metadata.
+ *
+ * @see \Drupal\Core\Render\AttachmentsResponseTrait
+ */
+interface AttachmentsResponseInterface {
+
+  /**
+   * Sets attachments for this response.
+   *
+   * Those can be processed by e.g. FinishResponseSubscriber for HtmlResponse's
+   * or processed directly by e.g. an AjaxResponse.
+   *
+   * @param array $attachments
+   *   An #attached array.
+   *
+   * @return $this
+   */
+  public function setAttachments(array $attachments);
+
+  /**
+   * Gets attachments set for this response.
+   *
+   * @return array $attachments
+   *   An #attached array.
+   */
+  public function getAttachments();
+
+
+}
diff --git a/core/lib/Drupal/Core/Render/AttachmentsResponseTrait.php b/core/lib/Drupal/Core/Render/AttachmentsResponseTrait.php
new file mode 100644
index 0000000..732aa1a
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/AttachmentsResponseTrait.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace Drupal\Core\Render;
+
+/**
+ * Provides an implementation of AttachmentsResponseInterface.
+ *
+ * @see \Drupal\Core\Render\AttachmentsResponseInterface
+ */
+trait AttachmentsResponseTrait {
+
+  /**
+   * The attachments for this response.
+   *
+   * @var array
+   */
+  protected $attachments = [
+    'library' => [],
+    'drupalSettings' => [],
+    'html_head' => [],
+    'feed' => [],
+    'html_head_link' => [],
+    'http_header' => [],
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setAttachments(array $attachments) {
+    $this->attachments = $attachments;
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getAttachments() {
+    return $this->attachments;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php b/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
index c8012c6..ae2fb42 100644
--- a/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
+++ b/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
@@ -7,6 +7,8 @@
 
 namespace Drupal\Core\Render;
 
+use Drupal\Core\EventSubscriber\FinishResponseSubscriber;
+
 /**
  * Default bare HTML page renderer.
  */
@@ -20,13 +22,21 @@ class BareHtmlPageRenderer implements BareHtmlPageRendererInterface {
   protected $renderer;
 
   /**
+   * The RenderCache service.
+   *
+   * @var \Drupal\Core\Render\RenderCache
+   */
+  protected $renderCache;
+
+  /**
    * Constructs a new BareHtmlPageRenderer.
    *
    * @param \Drupal\Core\Render\RendererInterface $renderer
    *   The renderer service.
    */
-  public function __construct(RendererInterface $renderer) {
+  public function __construct(RendererInterface $renderer, RenderCacheInterface $render_cache) {
     $this->renderer = $renderer;
+    $this->renderCache = $render_cache;
   }
 
   /**
@@ -55,16 +65,32 @@ public function renderBarePage(array $content, $title, $page_theme_property, arr
       $html['page']['highlighted'] = ['#type' => 'status_messages'];
     }
 
-    // We must first render the contents of the html.html.twig template, see
-    // \Drupal\Core\Render\MainContent\HtmlRenderer::renderResponse() for more
-    // information about this; the exact same pattern is used there and
-    // explained in detail there.
-    $this->renderer->render($html['page'], TRUE);
-
     // Add the bare minimum of attachments from the system module and the
     // current maintenance theme.
     system_page_attachments($html['page']);
-    return $this->renderer->render($html);
+    $this->renderer->renderRoot($html);
+    $content = $this->renderCache->getCacheableRenderArray($html);
+
+    // Never cache exception pages.
+    $content['#cache']['max-age'] = 0;
+    return $content;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function filterResponse(AttachmentsResponseInterface $response) {
+    FinishResponseSubscriber::processAttachments($response);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function filterRenderArray(array $build) {
+    $response = new CacheableHtmlResponse($build);
+    FinishResponseSubscriber::processAttachments($response);
+    return $response->getContent();
+  }
+
+
 }
diff --git a/core/lib/Drupal/Core/Render/CacheableHtmlResponse.php b/core/lib/Drupal/Core/Render/CacheableHtmlResponse.php
new file mode 100644
index 0000000..32f3b96
--- /dev/null
+++ b/core/lib/Drupal/Core/Render/CacheableHtmlResponse.php
@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Render\CacheableHtmlResponse.
+ */
+
+namespace Drupal\Core\Render;
+
+use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\Core\Cache\CacheableResponseInterface;
+use Drupal\Core\Cache\CacheableResponseTrait;
+
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * A response that contains and can expose cacheability metadata and attachments.
+ *
+ * Supports Drupal's caching concepts: cache tags for invalidation and cache
+ * contexts for variations.
+ *
+ * Supports Drupal's idea of #attached metadata: libraries, settings, http_header and html_head.
+ *
+ * @see \Drupal\Core\Cache\CacheableResponse
+ * @see \Drupal\Core\Render\AttachmentsResponseInterface
+ * @see \Drupal\Core\Render\AttachmentsResponseTrait
+ */
+class CacheableHtmlResponse extends Response implements CacheableResponseInterface, AttachmentsResponseInterface {
+
+  use CacheableResponseTrait;
+  use AttachmentsResponseTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setContent($content) {
+    // A render array can automatically be converted to a string and set the
+    // necessary metadata.
+    if (is_array($content) && (isset($content['#markup']))) {
+      $this->addCacheableDependency(CacheableMetadata::createFromRenderArray($content));
+      $this->setAttachments($content['#attached']);
+      $content = $content['#markup'];
+    }
+
+    parent::setContent($content);
+  }
+}
diff --git a/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php b/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
index addd13c..4f34f02 100644
--- a/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
+++ b/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php
@@ -13,6 +13,7 @@
 use Drupal\Core\Controller\TitleResolverInterface;
 use Drupal\Core\Display\PageVariantInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Render\CacheableHtmlResponse;
 use Drupal\Core\Render\PageDisplayVariantSelectionEvent;
 use Drupal\Core\Render\RenderCacheInterface;
 use Drupal\Core\Render\RendererInterface;
@@ -119,45 +120,22 @@ public function renderResponse(array $main_content, Request $request, RouteMatch
     // page.html.twig, hence add them here, just before rendering html.html.twig.
     $this->buildPageTopAndBottom($html);
 
-    // The three parts of rendered markup in html.html.twig (page_top, page and
-    // page_bottom) must be rendered with drupal_render_root(), so that their
-    // #post_render_cache callbacks are executed (which may attach additional
-    // assets).
-    // html.html.twig must be able to render the final list of attached assets,
-    // and hence may not execute any #post_render_cache_callbacks (because they
-    // might add yet more assets to be attached), and therefore it must be
-    // rendered with drupal_render(), not drupal_render_root().
-    $this->renderer->render($html['page'], TRUE);
-    if (isset($html['page_top'])) {
-      $this->renderer->render($html['page_top'], TRUE);
-    }
-    if (isset($html['page_bottom'])) {
-      $this->renderer->render($html['page_bottom'], TRUE);
-    }
-    $content = $this->renderer->render($html);
+    // @todo Make renderRoot return a cacheable render array directly.
+    $this->renderer->renderRoot($html);
+    $content = $this->renderCache->getCacheableRenderArray($html);
+
+    // Also associate the "rendered" cache tag. This allows us to invalidate the
+    // entire render cache, regardless of the cache bin.
+    $content['#cache']['tags'][] = 'rendered';
 
     // Set the generator in the HTTP header.
     list($version) = explode('.', \Drupal::VERSION, 2);
 
-    $response = new CacheableResponse($content, 200,[
+    $response = new CacheableHtmlResponse($content, 200,[
       'Content-Type' => 'text/html; charset=UTF-8',
       'X-Generator' => 'Drupal ' . $version . ' (https://www.drupal.org)'
     ]);
 
-    // Bubble the cacheability metadata associated with the rendered render
-    // arrays to the response.
-    foreach (['page_top', 'page', 'page_bottom'] as $region) {
-      if (isset($html[$region])) {
-        $response->addCacheableDependency(CacheableMetadata::createFromRenderArray($html[$region]));
-      }
-    }
-
-    // Also associate the "rendered" cache tag. This allows us to invalidate the
-    // entire render cache, regardless of the cache bin.
-    $default = new CacheableMetadata();
-    $default->setCacheTags(['rendered']);
-    $response->addCacheableDependency($default);
-
     return $response;
   }
 
diff --git a/core/modules/system/src/Controller/DbUpdateController.php b/core/modules/system/src/Controller/DbUpdateController.php
index 3c10c8a..926da6b 100644
--- a/core/modules/system/src/Controller/DbUpdateController.php
+++ b/core/modules/system/src/Controller/DbUpdateController.php
@@ -8,17 +8,18 @@
 namespace Drupal\system\Controller;
 
 use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Controller\ControllerBase;
 use Drupal\Core\Entity\EntityDefinitionUpdateManagerInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface;
 use Drupal\Core\Render\BareHtmlPageRendererInterface;
+use Drupal\Core\Render\CacheableHtmlResponse;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\Core\Site\Settings;
 use Drupal\Core\State\StateInterface;
 use Drupal\Core\Url;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpFoundation\Request;
 
 /**
@@ -198,7 +199,7 @@ public function handle($op, Request $request) {
     }
     $title = isset($output['#title']) ? $output['#title'] : $this->t('Drupal database update');
 
-    return new Response($this->bareHtmlPageRenderer->renderBarePage($output, $title, 'maintenance_page', $regions));
+    return new CacheableHtmlResponse($this->bareHtmlPageRenderer->renderBarePage($output, $title, 'maintenance_page', $regions));
   }
 
   /**