Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

core/lib/Drupal/Core/Controller/ControllerBase.php

@@ -33,7 +33,7 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  *
  * @see \Drupal\Core\DependencyInjection\ContainerInjectionInterface
  *
- * @ingroup menu
+ * @ingroup routing
  */
 abstract class ControllerBase implements ContainerInjectionInterface {
 

core/lib/Drupal/Core/Controller/TitleResolverInterface.php

@@ -17,18 +17,20 @@ interface TitleResolverInterface {
   /**
    * Returns a static or dynamic title for the route.
    *
-   * The returned title string must be safe to output in HTML. For example, an
-   * implementation should call \Drupal\Component\Utility\SafeMarkup::checkPlain()
-   * or \Drupal\Component\Utility\Xss::filterAdmin() on the string, or use
-   * appropriate placeholders to sanitize dynamic content inside a localized
-   * string before returning it. The title may contain HTML such as EM tags.
+   * If the returned title can contain HTML that should not be escaped it should
+   * return a render array, for example:
+   * @code
+   * ['#markup' => 'title', '#allowed_tags' => ['em']]
+   * @endcode
+   * If the method returns a string and it is not marked safe then it will be
+   * auto-escaped.
    *
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   The request object passed to the title callback.
    * @param \Symfony\Component\Routing\Route $route
    *   The route information of the route to fetch the title.
    *
-   * @return string|null
+   * @return array|string|null
    *   The title for the route.
    */
   public function getTitle(Request $request, Route $route);