diff --git a/core/lib/Drupal/Core/Controller/ExceptionController.php b/core/lib/Drupal/Core/Controller/ExceptionController.php
index 01a4253..bc1177f 100644
--- a/core/lib/Drupal/Core/Controller/ExceptionController.php
+++ b/core/lib/Drupal/Core/Controller/ExceptionController.php
@@ -10,7 +10,7 @@
 use Drupal\Core\Page\DefaultHtmlPageRenderer;
 use Drupal\Core\Page\HtmlFragmentRendererInterface;
 use Drupal\Core\Page\HtmlPageRendererInterface;
-use Drupal\Core\Page\RenderHtmlRenderer;
+use Drupal\Core\Page\RenderHtmlRendererInterface;
 use Symfony\Component\DependencyInjection\ContainerAwareInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
@@ -77,7 +77,7 @@ class ExceptionController extends HtmlControllerBase implements ContainerAwareIn
    * @param \Drupal\Core\Page\RenderHtmlRenderer
    *   The render array converter.
    */
-  public function __construct(ContentNegotiation $negotiation, TitleResolverInterface $title_resolver, HtmlPageRendererInterface $renderer, HtmlFragmentRendererInterface $fragment_renderer, TranslationInterface $string_translation, RenderHtmlRenderer $render_converter) {
+  public function __construct(ContentNegotiation $negotiation, TitleResolverInterface $title_resolver, HtmlPageRendererInterface $renderer, HtmlFragmentRendererInterface $fragment_renderer, TranslationInterface $string_translation, RenderHtmlRendererInterface $render_converter) {
     parent::__construct($title_resolver, $render_converter);
     $this->negotiation = $negotiation;
     $this->htmlPageRenderer = $renderer;
diff --git a/core/lib/Drupal/Core/Controller/HtmlControllerBase.php b/core/lib/Drupal/Core/Controller/HtmlControllerBase.php
index 9bab08e..0da21d2 100644
--- a/core/lib/Drupal/Core/Controller/HtmlControllerBase.php
+++ b/core/lib/Drupal/Core/Controller/HtmlControllerBase.php
@@ -8,7 +8,7 @@
 namespace Drupal\Core\Controller;
 
 use Drupal\Core\Page\HtmlFragment;
-use Drupal\Core\Page\RenderHtmlRenderer;
+use Drupal\Core\Page\RenderHtmlRendererInterface;
 use Drupal\Core\Utility\Title;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 use Symfony\Component\HttpFoundation\Request;
@@ -29,7 +29,7 @@ class HtmlControllerBase {
   /**
    * The render array converter.
    *
-   * @var \Drupal\Core\Page\RenderHtmlRenderer
+   * @var RenderHtmlRendererInterface
    */
   protected $renderConverter;
 
@@ -43,7 +43,7 @@ class HtmlControllerBase {
    * @param \Drupal\Core\Page\RenderHtmlRenderer
    *   The render array converter.
    */
-  public function __construct(TitleResolverInterface $title_resolver, RenderHtmlRenderer $render_converter) {
+  public function __construct(TitleResolverInterface $title_resolver, RenderHtmlRendererInterface $render_converter) {
     $this->titleResolver = $title_resolver;
     $this->renderConverter = $render_converter;
   }
diff --git a/core/lib/Drupal/Core/Controller/HtmlPageController.php b/core/lib/Drupal/Core/Controller/HtmlPageController.php
index 8cbbf60..c070449 100644
--- a/core/lib/Drupal/Core/Controller/HtmlPageController.php
+++ b/core/lib/Drupal/Core/Controller/HtmlPageController.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Controller;
 
 use Drupal\Core\Page\RenderHtmlRenderer;
+use Drupal\Core\Page\RenderHtmlRendererInterface;
 use Drupal\Core\Routing\UrlGeneratorInterface;
 use Symfony\Component\HttpFoundation\Request;
 
@@ -35,7 +36,7 @@ class HtmlPageController extends HtmlControllerBase {
    * @param \Drupal\Core\Page\RenderHtmlRenderer
    *   The render array converter.
    */
-  public function __construct(ControllerResolverInterface $controller_resolver, TitleResolverInterface $title_resolver, RenderHtmlRenderer $render_converter) {
+  public function __construct(ControllerResolverInterface $controller_resolver, TitleResolverInterface $title_resolver, RenderHtmlRendererInterface $render_converter) {
     parent::__construct($title_resolver, $render_converter);
 
     $this->controllerResolver = $controller_resolver;
diff --git a/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php b/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
index 294c128..1c552f3 100644
--- a/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
+++ b/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
@@ -10,7 +10,7 @@
 use Drupal\Core\Routing\UrlGeneratorInterface;
 use Drupal\Core\Utility\Title;
 
-class RenderHtmlRenderer {
+class RenderHtmlRenderer implements RenderHtmlRendererInterface {
 
   /**
    * @var \Drupal\Core\Routing\UrlGeneratorInterface
@@ -28,13 +28,7 @@ public function __construct(UrlGeneratorInterface $generator) {
   }
 
   /**
-   * Converts a render array into a corresponding HtmlFragment object.
-   *
-   * @param array|string $render_array
-   *   The render array to convert. A string may also be passed, in which case
-   *   it will be treated as a a render array with just a #markup property.
-   * @return HtmlFragment
-   *   The equivalent HtmlFragment object.
+   * {@inheritdoc}
    */
   public function render($render_array) {
     if (!is_array($render_array)) {
diff --git a/core/lib/Drupal/Core/Page/RenderHtmlRendererInterface.php b/core/lib/Drupal/Core/Page/RenderHtmlRendererInterface.php
new file mode 100644
index 0000000..30f6ca7
--- /dev/null
+++ b/core/lib/Drupal/Core/Page/RenderHtmlRendererInterface.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Page\RenderHtmlRendererInterface.
+ */
+
+namespace Drupal\Core\Page;
+
+interface RenderHtmlRendererInterface {
+
+  /**
+   * Converts a render array into a corresponding HtmlFragment object.
+   *
+   * @param array|string $render_array
+   *   The render array to convert. A string may also be passed, in which case
+   *   it will be treated as a a render array with just a #markup property.
+   * @return HtmlFragment
+   *   The equivalent HtmlFragment object.
+   */
+  public function render($render_array);
+}
diff --git a/core/tests/Drupal/Tests/Core/Controller/ExceptionControllerTest.php b/core/tests/Drupal/Tests/Core/Controller/ExceptionControllerTest.php
index 7307780..034c1fc 100644
--- a/core/tests/Drupal/Tests/Core/Controller/ExceptionControllerTest.php
+++ b/core/tests/Drupal/Tests/Core/Controller/ExceptionControllerTest.php
@@ -26,6 +26,7 @@ public function test405HTML() {
     $flat_exception = FlattenException::create($exception, 405);
     $html_page_renderer = $this->getMock('Drupal\Core\Page\HtmlPageRendererInterface');
     $html_fragment_renderer = $this->getMock('Drupal\Core\Page\HtmlFragmentRendererInterface');
+    $render_array_renderer = $this->getMock('Drupal\Core\Page\RenderArrayRendererInterface');
     $title_resolver = $this->getMock('Drupal\Core\Controller\TitleResolverInterface');
     $translation = $this->getMock('Drupal\Core\StringTranslation\TranslationInterface');
     $url_generator = $this->getMock('Drupal\Core\Routing\UrlGeneratorInterface');
@@ -35,7 +36,7 @@ public function test405HTML() {
       ->method('getContentType')
       ->will($this->returnValue('html'));
 
-    $exception_controller = new ExceptionController($content_negotiation, $title_resolver, $html_page_renderer, $html_fragment_renderer, $translation, $url_generator);
+    $exception_controller = new ExceptionController($content_negotiation, $title_resolver, $html_page_renderer, $html_fragment_renderer, $translation, $url_generator, $render_array_renderer);
     $response = $exception_controller->execute($flat_exception, new Request());
     $this->assertEquals($response->getStatusCode(), 405, 'HTTP status of response is correct.');
     $this->assertEquals($response->getContent(), 'Method Not Allowed', 'HTTP response body is correct.');