diff --git a/core/core.services.yml b/core/core.services.yml
index 2799eaf..922a110 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -580,7 +580,7 @@ services:
       - { name: event_subscriber }
     arguments: ['@html_fragment_renderer', '@html_page_renderer']
   render_array_renderer:
-    class: Drupal\Core\Page\RenderHtmlFragmentConverter
+    class: Drupal\Core\Page\RenderHtmlRenderer
     arguments: ['@url_generator']
   html_fragment_renderer:
     class: Drupal\Core\Page\DefaultHtmlFragmentRenderer
@@ -678,7 +678,7 @@ services:
     arguments: ['@config.manager', '@config.storage', '@config.storage.snapshot']
   exception_controller:
     class: Drupal\Core\Controller\ExceptionController
-    arguments: ['@content_negotiation', '@title_resolver', '@html_page_renderer', '@html_fragment_renderer', '@string_translation']
+    arguments: ['@content_negotiation', '@title_resolver', '@html_page_renderer', '@html_fragment_renderer', '@string_translation', '@render_array_renderer']
     calls:
       - [setContainer, ['@service_container']]
   exception_listener:
diff --git a/core/lib/Drupal/Core/Controller/ExceptionController.php b/core/lib/Drupal/Core/Controller/ExceptionController.php
index db4807b..01a4253 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\RenderHtmlFragmentConverter;
+use Drupal\Core\Page\RenderHtmlRenderer;
 use Symfony\Component\DependencyInjection\ContainerAwareInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
@@ -74,10 +74,10 @@ class ExceptionController extends HtmlControllerBase implements ContainerAwareIn
    * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
    *   The url generator.
    * @param \Drupal\Core\Routing\UrlGeneratorInterface $url_generator
-   * @param \Drupal\Core\Page\RenderHtmlFragmentConverter
+   * @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, RenderHtmlFragmentConverter $render_converter) {
+  public function __construct(ContentNegotiation $negotiation, TitleResolverInterface $title_resolver, HtmlPageRendererInterface $renderer, HtmlFragmentRendererInterface $fragment_renderer, TranslationInterface $string_translation, RenderHtmlRenderer $render_converter) {
     parent::__construct($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 484d041..9bab08e 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\RenderHtmlFragmentConverter;
+use Drupal\Core\Page\RenderHtmlRenderer;
 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\RenderHtmlFragmentConverter
+   * @var \Drupal\Core\Page\RenderHtmlRenderer
    */
   protected $renderConverter;
 
@@ -40,10 +40,10 @@ class HtmlControllerBase {
    *   The title resolver.
    * @param \Drupal\Core\Routing\UrlGeneratorInterface $url_generator
    *   The url generator.
-   * @param \Drupal\Core\Page\RenderHtmlFragmentConverter
+   * @param \Drupal\Core\Page\RenderHtmlRenderer
    *   The render array converter.
    */
-  public function __construct(TitleResolverInterface $title_resolver, RenderHtmlFragmentConverter $render_converter) {
+  public function __construct(TitleResolverInterface $title_resolver, RenderHtmlRenderer $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 10034b5..8cbbf60 100644
--- a/core/lib/Drupal/Core/Controller/HtmlPageController.php
+++ b/core/lib/Drupal/Core/Controller/HtmlPageController.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Core\Controller;
 
-use Drupal\Core\Page\RenderHtmlFragmentConverter;
+use Drupal\Core\Page\RenderHtmlRenderer;
 use Drupal\Core\Routing\UrlGeneratorInterface;
 use Symfony\Component\HttpFoundation\Request;
 
@@ -32,10 +32,10 @@ class HtmlPageController extends HtmlControllerBase {
    *   The title resolver.
    * @param \Drupal\Core\Routing\UrlGeneratorInterface $url_generator
    *   The url generator.
-   * @param \Drupal\Core\Page\RenderHtmlFragmentConverter
+   * @param \Drupal\Core\Page\RenderHtmlRenderer
    *   The render array converter.
    */
-  public function __construct(ControllerResolverInterface $controller_resolver, TitleResolverInterface $title_resolver, RenderHtmlFragmentConverter $render_converter) {
+  public function __construct(ControllerResolverInterface $controller_resolver, TitleResolverInterface $title_resolver, RenderHtmlRenderer $render_converter) {
     parent::__construct($title_resolver, $render_converter);
 
     $this->controllerResolver = $controller_resolver;
diff --git a/core/lib/Drupal/Core/Page/RenderHtmlFragmentConverter.php b/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
similarity index 83%
rename from core/lib/Drupal/Core/Page/RenderHtmlFragmentConverter.php
rename to core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
index 3f79159..294c128 100644
--- a/core/lib/Drupal/Core/Page/RenderHtmlFragmentConverter.php
+++ b/core/lib/Drupal/Core/Page/RenderHtmlRenderer.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\Core\Page\RenderHtmlFragmentConverter.
+ * Contains \Drupal\Core\Page\RenderHtmlRenderer.
  */
 
 namespace Drupal\Core\Page;
@@ -10,7 +10,7 @@
 use Drupal\Core\Routing\UrlGeneratorInterface;
 use Drupal\Core\Utility\Title;
 
-class RenderHtmlFragmentConverter {
+class RenderHtmlRenderer {
 
   /**
    * @var \Drupal\Core\Routing\UrlGeneratorInterface
@@ -18,7 +18,7 @@ class RenderHtmlFragmentConverter {
   protected $urlGenerator;
 
   /**
-   * Constructs a new RenderHtmlFragmentConverter.
+   * Constructs a new RenderHtmlRenderer.
    *
    * @param UrlGeneratorInterface $generator
    *   The URL Generator service.
@@ -30,12 +30,13 @@ public function __construct(UrlGeneratorInterface $generator) {
   /**
    * Converts a render array into a corresponding HtmlFragment object.
    *
-   * @param array $render_array
-   *   The render array to convert.
+   * @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(array $render_array) {
+  public function render($render_array) {
     if (!is_array($render_array)) {
       $render_array = array(
         'main' => array(
@@ -48,8 +49,6 @@ public function render(array $render_array) {
     $cache = !empty($render_array['#cache']['tags']) ? ['tags' => $render_array['#cache']['tags']] : [];
     $fragment = new HtmlFragment($content, $cache);
 
-
-
     // A title defined in the return always wins.
     if (isset($render_array['#title'])) {
       $fragment->setTitle($render_array['#title'], Title::FILTER_XSS_ADMIN);