diff --git a/core/core.services.yml b/core/core.services.yml
index b6decf3..a1648c9 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -339,7 +339,7 @@ services:
       - { name: event_subscriber }
   router.route_preloader:
     class: Drupal\Core\Routing\RoutePreloader
-    arguments: ['@router.route_provider', '@state', '@content_negotiation']
+    arguments: ['@router.route_provider', '@state']
     tags:
       - { name: 'event_subscriber' }
   router.matcher.final_matcher:
@@ -515,12 +515,12 @@ services:
       - { name: event_subscriber }
     arguments: ['@router', '@router.request_context', NULL, '@request_stack']
   content_negotiation:
-    class: Drupal\Core\ContentNegotiation
+    class: Negotiation\FormatNegotiator
   view_subscriber:
     class: Drupal\Core\EventSubscriber\ViewSubscriber
     tags:
       - { name: event_subscriber }
-    arguments: ['@content_negotiation', '@title_resolver', '@ajax_response_renderer']
+    arguments: ['@title_resolver', '@ajax_response_renderer']
   html_view_subscriber:
     class: Drupal\Core\EventSubscriber\HtmlViewSubscriber
     tags:
diff --git a/core/lib/Drupal/Core/EventSubscriber/ContentControllerSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/ContentControllerSubscriber.php
index 377ae93..9fae03e 100644
--- a/core/lib/Drupal/Core/EventSubscriber/ContentControllerSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ContentControllerSubscriber.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Core\EventSubscriber;
 
-use Drupal\Core\ContentNegotiation;
+use Negotiation\FormatNegotiatorInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpKernel\Event\GetResponseEvent;
 use Symfony\Component\HttpKernel\KernelEvents;
@@ -20,17 +20,17 @@ class ContentControllerSubscriber implements EventSubscriberInterface {
   /**
    * Content negotiation library.
    *
-   * @var \Drupal\Core\ContentNegotiation
+   * @var \Negotiation\FormatNegotiatorInterface
    */
   protected $negotiation;
 
   /**
    * Constructs a new ContentControllerSubscriber object.
    *
-   * @param \Drupal\Core\ContentNegotiation $negotiation
+   * @param \Negotiation\FormatNegotiatorInterface $negotiation
    *   The Content Negotiation service.
    */
-  public function __construct(ContentNegotiation $negotiation) {
+  public function __construct(FormatNegotiatorInterface $negotiation) {
     $this->negotiation = $negotiation;
   }
 
@@ -56,7 +56,16 @@ public function onRequestDeriveFormat(GetResponseEvent $event) {
     $request = $event->getRequest();
 
     if (!$request->attributes->get('_format')) {
-      $request->setRequestFormat($this->negotiation->getContentType($request));
+      // The following formats have special high-priority according to Drupal.
+      // Any other formats should negotiate in order as appropriate.
+      $priorities = array('text/html', 'application/vnd.drupal-ajax', 'application/vnd.drupal-modal', 'application/vnd.drupal-dialog');
+
+      // Because we're registering new formats on the Request object, we will
+      // retrieve the raw mime type and then let the request map that to
+      // the format machine name. That way we only need to register new formats
+      // on the one object.
+      $format = $this->negotiation->getBest($accept_header = $request->headers->get('Accept'), $priorities);
+      $request->setRequestFormat($request->getFormat($format->getValue()));
     }
   }
 
@@ -84,7 +93,7 @@ public function onRequestDeriveContentWrapper(GetResponseEvent $event) {
    *   An array of event listener definitions.
    */
   static function getSubscribedEvents() {
-    $events[KernelEvents::REQUEST][] = array('onRequestDeriveFormat', 31);
+    $events[KernelEvents::REQUEST][] = array('onRequestDeriveFormat', 33);
     $events[KernelEvents::REQUEST][] = array('onRequestDeriveContentWrapper', 30);
 
     return $events;
diff --git a/core/lib/Drupal/Core/EventSubscriber/ViewSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/ViewSubscriber.php
index 84b94c9..91eba40 100644
--- a/core/lib/Drupal/Core/EventSubscriber/ViewSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ViewSubscriber.php
@@ -18,8 +18,6 @@
 use Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
-use Drupal\Core\ContentNegotiation;
-
 /**
  * Main subscriber for VIEW HTTP responses.
  *
@@ -53,15 +51,12 @@ class ViewSubscriber implements EventSubscriberInterface {
   /**
    * Constructs a new ViewSubscriber.
    *
-   * @param \Drupal\Core\ContentNegotiation $negotiation
-   *   The content negotiation.
    * @param \Drupal\Core\Controller\TitleResolverInterface $title_resolver
    *   The title resolver.
    * @param \Drupal\Core\Ajax\AjaxResponseRenderer $ajax_renderer
    *   The ajax response renderer.
    */
-  public function __construct(ContentNegotiation $negotiation, TitleResolverInterface $title_resolver, AjaxResponseRenderer $ajax_renderer) {
-    $this->negotiation = $negotiation;
+  public function __construct(TitleResolverInterface $title_resolver, AjaxResponseRenderer $ajax_renderer) {
     $this->titleResolver = $title_resolver;
     $this->ajaxRenderer = $ajax_renderer;
   }
@@ -88,7 +83,7 @@ public function onView(GetResponseForControllerResultEvent $event) {
     // object.  The subrequest's response will get dissected and placed into
     // the larger page as needed.
     if ($event->getRequestType() == HttpKernelInterface::MASTER_REQUEST) {
-      $method = 'on' . $this->negotiation->getContentType($request);
+      $method = 'on' . $request->getRequestFormat();
 
       if (method_exists($this, $method)) {
         $event->setResponse($this->$method($event));
diff --git a/core/lib/Drupal/Core/Routing/AcceptHeaderMatcher.php b/core/lib/Drupal/Core/Routing/AcceptHeaderMatcher.php
index 34f0ae5..d964cc0 100644
--- a/core/lib/Drupal/Core/Routing/AcceptHeaderMatcher.php
+++ b/core/lib/Drupal/Core/Routing/AcceptHeaderMatcher.php
@@ -8,7 +8,7 @@
 namespace Drupal\Core\Routing;
 
 use Drupal\Component\Utility\String;
-use Drupal\Core\ContentNegotiation;
+use Negotiation\FormatNegotiatorInterface;
 use Symfony\Cmf\Component\Routing\NestedMatcher\RouteFilterInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException;
@@ -22,18 +22,18 @@ class AcceptHeaderMatcher implements RouteFilterInterface {
   /**
    * The content negotiation library.
    *
-   * @var \Drupal\Core\ContentNegotiation
+   * @var \Negotiation\FormatNegotiatorInterface
    */
-  protected $contentNegotiation;
+  protected $negotiation;
 
   /**
    * Constructs a new AcceptHeaderMatcher.
    *
-   * @param \Drupal\Core\ContentNegotiation $cotent_negotiation
+   * @param \Negotiation\FormatNegotiatorInterface; $negotiation
    *   The content negotiation library.
    */
-  public function __construct(ContentNegotiation $content_negotiation) {
-    $this->contentNegotiation = $content_negotiation;
+  public function __construct(FormatNegotiatorInterface $negotiation) {
+    $this->negotiation = $negotiation;
   }
 
   /**
@@ -44,7 +44,7 @@ public function filter(RouteCollection $collection, Request $request) {
     // @todo replace by proper content negotiation library.
     $acceptable_mime_types = $request->getAcceptableContentTypes();
     $acceptable_formats = array_filter(array_map(array($request, 'getFormat'), $acceptable_mime_types));
-    $primary_format = $this->contentNegotiation->getContentType($request);
+    $primary_format = $request->getRequestFormat();
 
     foreach ($collection as $name => $route) {
       // _format could be a |-delimited list of supported formats.
diff --git a/core/lib/Drupal/Core/Routing/RoutePreloader.php b/core/lib/Drupal/Core/Routing/RoutePreloader.php
index 7952d17..8e8d230 100644
--- a/core/lib/Drupal/Core/Routing/RoutePreloader.php
+++ b/core/lib/Drupal/Core/Routing/RoutePreloader.php
@@ -38,13 +38,6 @@ class RoutePreloader implements EventSubscriberInterface {
   protected $state;
 
   /**
-   * The content negotiation.
-   *
-   * @var \Drupal\Core\ContentNegotiation
-   */
-  protected $negotiation;
-
-  /**
    * Contains the non-admin routes while rebuilding the routes.
    *
    * @var array
@@ -58,13 +51,10 @@ class RoutePreloader implements EventSubscriberInterface {
    *   The route provider.
    * @param \Drupal\Core\State\StateInterface $state
    *   The state key value store.
-   * @param \Drupal\Core\ContentNegotiation $negotiation
-   *   The content negotiation.
    */
-  public function __construct(RouteProviderInterface $route_provider, StateInterface $state, ContentNegotiation $negotiation) {
+  public function __construct(RouteProviderInterface $route_provider, StateInterface $state) {
     $this->routeProvider = $route_provider;
     $this->state = $state;
-    $this->negotiation = $negotiation;
   }
 
   /**
@@ -75,7 +65,7 @@ public function __construct(RouteProviderInterface $route_provider, StateInterfa
    */
   public function onRequest(KernelEvent $event) {
     // Just preload on normal HTML pages, as they will display menu links.
-    if ($this->negotiation->getContentType($event->getRequest()) == 'html') {
+    if ($event->getRequest()->getRequestFormat() == 'html') {
       $this->loadNonAdminRoutes();
     }
   }