Issue #2068437 by dawehner, pwolanin: Fixed _title does not work on _form.

core/lib/Drupal/Core/EventSubscriber/ViewSubscriber.php

@@ -71,6 +71,12 @@ public function onView(GetResponseForControllerResultEvent $event) {
           '#markup' => $page_result,
         );
       }
+
+      // If no title was returned fall back to one defined in the route.
+      if (!isset($page_result['#title']) && $request->attributes->has('_title')) {
+        $page_result['#title'] = $request->attributes->get('_title');
+      }
+
       $event->setResponse(new Response(drupal_render_page($page_result)));
     }
     else {
@@ -83,6 +89,12 @@ public function onView(GetResponseForControllerResultEvent $event) {
           '#markup' => $page_result,
         );
       }
+
+      // If no title was returned fall back to one defined in the route.
+      if (!isset($page_result['#title']) && $request->attributes->has('_title')) {
+        $page_result['#title'] = $request->attributes->get('_title');
+      }
+
       $event->setResponse(new Response(drupal_render($page_result)));
     }
   }

core/modules/overlay/lib/Drupal/overlay/Tests/OverlayRenderTest.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\overlay\Tests\OverlayRenderTest.
+ */
+
+namespace Drupal\overlay\Tests;
+
+use Drupal\simpletest\WebTestBase;
+
+/**
+ * Tests the rendering of a page in an overlay.
+ */
+class OverlayRenderTest extends WebTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('test_page_test', 'overlay');
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Overlay child page rendering',
+      'description' => 'Tests the rendering of a page in an overlay.',
+      'group' => 'Overlay',
+    );
+  }
+
+  /**
+   * Tests the title of a page in an overlay.
+   */
+  public function testOverlayTitle() {
+    $account = $this->drupalCreateUser(array('access overlay'));
+    $this->drupalLogin($account);
+
+    $this->drupalGet('admin/test-render-title', array('query' => array('render' => 'overlay')));
+    $result = $this->xpath('//h1[@id = "overlay-title"]');
+    $this->assertEqual((string) $result[0], 'Foo');
+  }
+
+}

core/modules/overlay/overlay.module

@@ -5,6 +5,7 @@
  * Displays the Drupal administration interface in an overlay.
  */
 
+use Drupal\Core\Template\RenderWrapper;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
@@ -360,7 +361,13 @@ function overlay_preprocess_maintenance_page(&$variables) {
  */
 function template_preprocess_overlay(&$variables) {
   $variables['tabs'] = menu_primary_local_tasks();
-  $variables['title'] = drupal_get_title();
+
+  if (isset($variables['page']['#title'])) {
+    $variables['title'] = $variables['page']['#title'];
+  }
+  else {
+    $variables['title'] = new RenderWrapper('drupal_get_title');
+  }
   $variables['disable_overlay'] = overlay_disable_message();
 
   // Add attributes for the overlay container.

core/modules/system/lib/Drupal/system/Tests/System/PageTitleTest.php

@@ -19,7 +19,7 @@ class PageTitleTest extends WebTestBase {
    *
    * @var array
    */
-  public static $modules = array('node', 'test_page_test');
+  public static $modules = array('node', 'test_page_test', 'form_test');
 
   protected $content_user;
   protected $saved_title;
@@ -136,6 +136,20 @@ public function testRenderTitle() {
     $this->assertTitle('Foo | Drupal');
     $result = $this->xpath('//h1');
     $this->assertEqual('Foo', (string) $result[0]);
+
+    // Test a controller using _controller instead of _content.
+    $this->drupalGet('test-render-title-controller');
+
+    $this->assertTitle('Foo | Drupal');
+    $result = $this->xpath('//h1');
+    $this->assertEqual('Foo', (string) $result[0]);
+
+    // Test forms
+    $this->drupalGet('form-test/object-builder');
+
+    $this->assertTitle('Test dynamic title | Drupal');
+    $result = $this->xpath('//h1');
+    $this->assertEqual('Test dynamic title', (string) $result[0]);
   }
 
 }

core/modules/system/tests/modules/form_test/lib/Drupal/form_test/FormTestObject.php

@@ -37,6 +37,9 @@ public function buildForm(array $form, array &$form_state) {
       '#type' => 'submit',
       '#value' => $this->t('Save'),
     );
+
+    $form['#title'] = 'Test dynamic title';
+
     return $form;
   }
 

core/modules/system/tests/modules/test_page_test/test_page_test.routing.yml

@@ -4,3 +4,18 @@ test_page_render_title:
     _content: 'Drupal\test_page_test\Controller\Test::renderTitle'
   requirements:
     _access: 'TRUE'
+
+admin_test_page_render_title:
+  pattern: "/admin/test-render-title"
+  defaults:
+    _content: 'Drupal\test_page_test\Controller\Test::renderTitle'
+  requirements:
+    _access: 'TRUE'
+
+test_page_render_title_controller:
+  pattern: "/test-render-title-controller"
+  defaults:
+    _controller: 'Drupal\test_page_test\Controller\Test::renderTitle'
+  requirements:
+    _access: 'TRUE'
+