diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index cf0e3dd..af355f7 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -207,11 +207,6 @@
 define('REQUEST_TIME', (int) $_SERVER['REQUEST_TIME']);
 
 /**
- * Flag for drupal_set_title(); text is not sanitized, so run check_plain().
- */
-const CHECK_PLAIN = 0;
-
-/**
  * Flag for drupal_set_title(); text has already been sanitized.
  */
 const PASS_THROUGH = -1;
@@ -1727,7 +1722,7 @@ function drupal_get_title() {
  * @return
  *   The updated title of the current page.
  */
-function drupal_set_title($title = NULL, $output = CHECK_PLAIN) {
+function drupal_set_title($title = NULL, $output = String::CHECK_PLAIN) {
   $stored_title = &drupal_static(__FUNCTION__);
 
   if (isset($title)) {
diff --git a/core/includes/common.inc b/core/includes/common.inc
index a392a5a..30631a0 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -4552,6 +4552,18 @@ function drupal_render_page($page) {
     $page['content']['system_main'] = drupal_set_page_content();
   }
 
+  // Set page title, if exist.
+  array_walk_recursive($page, function($value) {
+    if (isset($values['#page_title'])) {
+      // Check for title output flag.
+      if (!isset($value['#page_title_output']) || !in_array($value['#page_title_output'], array(String::CHECK_PLAIN, PASS_THROUGH))) {
+        $page['#page_title_output'] = STRING::CHECK_PLAIN;
+      }
+
+      drupal_set_title($value['#page_title'], $value['#page_title_output']);
+    }
+  });
+
   return drupal_render($page);
 }
 
diff --git a/core/lib/Drupal/Component/Utility/String.php b/core/lib/Drupal/Component/Utility/String.php
index 3cd6472..44d6915 100644
--- a/core/lib/Drupal/Component/Utility/String.php
+++ b/core/lib/Drupal/Component/Utility/String.php
@@ -13,6 +13,11 @@
 class String {
 
   /**
+   * Flag for drupal_set_title(); text is not sanitized, so run String::checkPlain().
+   */
+  const CHECK_PLAIN = 0;
+
+  /**
    * Encodes special characters in a plain-text string for display as HTML.
    *
    * Also validates strings as UTF-8.
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/PageTitleFilteringTest.php b/core/modules/system/lib/Drupal/system/Tests/System/PageTitleTest.php
similarity index 88%
rename from core/modules/system/lib/Drupal/system/Tests/System/PageTitleFilteringTest.php
rename to core/modules/system/lib/Drupal/system/Tests/System/PageTitleTest.php
index 9d96be8..2dcfb66 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/PageTitleFilteringTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/PageTitleTest.php
@@ -7,17 +7,18 @@
 
 namespace Drupal\system\Tests\System;
 
+use Drupal\Component\Utility\String;
 use Drupal\Core\Language\Language;
 use Drupal\simpletest\WebTestBase;
 
-class PageTitleFilteringTest extends WebTestBase {
+class PageTitleTest extends WebTestBase {
 
   /**
    * Modules to enable.
    *
    * @var array
    */
-  public static $modules = array('node');
+  public static $modules = array('node', 'test_page_test');
 
   protected $content_user;
   protected $saved_title;
@@ -27,7 +28,7 @@ class PageTitleFilteringTest extends WebTestBase {
    */
   public static function getInfo() {
     return array(
-      'name' => 'HTML in page titles',
+      'name' => 'Page titles',
       'description' => 'Tests correct handling or conversion by drupal_set_title() and drupal_get_title() and checks the correct escaping of site name and slogan.',
       'group' => 'System'
     );
@@ -59,11 +60,11 @@ function tearDown() {
   /**
    * Tests the handling of HTML by drupal_set_title() and drupal_get_title()
    */
-  function testTitleTags() {
+  function ptestTitleTags() {
     $title = "string with <em>HTML</em>";
     // drupal_set_title's $filter is CHECK_PLAIN by default, so the title should be
     // returned with check_plain().
-    drupal_set_title($title, CHECK_PLAIN);
+    drupal_set_title($title, String::CHECK_PLAIN);
     $this->assertTrue(strpos(drupal_get_title(), '<em>') === FALSE, 'Tags in title converted to entities when $output is CHECK_PLAIN.');
     // drupal_set_title's $filter is passed as PASS_THROUGH, so the title should be
     // returned with HTML.
@@ -86,7 +87,7 @@ function testTitleTags() {
   /**
    * Test if the title of the site is XSS proof.
    */
-  function testTitleXSS() {
+  function ptestTitleXSS() {
     // Set some title with JavaScript and HTML chars to escape.
     $title = '</title><script type="text/javascript">alert("Title XSS!");</script> & < > " \' ';
     $title_filtered = check_plain($title);
@@ -122,4 +123,15 @@ function testTitleXSS() {
     $this->assertNoRaw($slogan, 'Check for the unfiltered version of the slogan.');
     $this->assertRaw($slogan_filtered, 'Check for the filtered version of the slogan.');
   }
+
+  /**
+   * Tests the page title of render arrays.
+   *
+   * @see \Drupal\test_page_test\Controller\Test::renderTitle()
+   */
+  public function testRenderTitle() {
+    $this->drupalGet('test-render-title');
+    $this->assertTitle(t('Foo'));
+  }
+
 }
diff --git a/core/modules/system/tests/modules/test_page_test/lib/Drupal/test_page_test/Controller/Test.php b/core/modules/system/tests/modules/test_page_test/lib/Drupal/test_page_test/Controller/Test.php
new file mode 100644
index 0000000..2bf2d96
--- /dev/null
+++ b/core/modules/system/tests/modules/test_page_test/lib/Drupal/test_page_test/Controller/Test.php
@@ -0,0 +1,26 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\test_page_test\Controller\Test.
+ */
+
+namespace Drupal\test_page_test\Controller;
+
+class Test {
+
+  /**
+   * Renders a page with a title.
+   *
+   * @return array
+   *   A render array as expected by drupal_render()
+   */
+  public function renderTitle() {
+    $build = array();
+    $build['#markup'] = t('Hello Drupal');
+    $build['#page_title'] = t('Foo');
+
+    return $build;
+  }
+
+}
diff --git a/core/modules/system/tests/modules/test_page_test/test_page_test.routing.yml b/core/modules/system/tests/modules/test_page_test/test_page_test.routing.yml
new file mode 100644
index 0000000..0f45d10
--- /dev/null
+++ b/core/modules/system/tests/modules/test_page_test/test_page_test.routing.yml
@@ -0,0 +1,6 @@
+test_page_render_title:
+  pattern: "/test-render-title"
+  defaults:
+    _content: 'Drupal\test_page_test\Controller\Test::renderTitle'
+  requirements:
+    _access: 'TRUE'