Allow WebUI Tests to use preLoad in HtmlDialogUI.

chrome/test/data/webui/hung_renderer_dialog_test.js

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * Test fixture for generated tests.
  * @extends {testing.Test}
  */
 function HungRendererDialogUITest() {};
 
 HungRendererDialogUITest.prototype = {
   __proto__: testing.Test.prototype,
 
   /**
    * Define the C++ fixture class and include it.
    * @type {?string}
    * @override
    */
   typedefCppFixture: 'HungRendererDialogUITest',
+
+  /**
+   * Show the hung renderer dialog.
+   */
+  testGenPreamble: function() {
+    GEN('ShowHungRendererDialogInternal();');
+  },
 };
 
 // Include the bulk of c++ code.
 GEN('#include "chrome/test/data/webui/hung_renderer_dialog_ui_test-inl.h"');
 
 // Constructors and destructors must be provided in .cc to prevent clang errors.
 GEN('HungRendererDialogUITest::HungRendererDialogUITest() {}');
 GEN('HungRendererDialogUITest::~HungRendererDialogUITest() {}');
 
 /**
@@ skipping 24 matching lines @@
   assertNotEquals(null, tabTable);
   assertGT(tabTable.childElementCount, 0);
 
   var children = tabTable.getElementsByTagName('*');
   assertNotEquals(null, children);
   var titleElement = children[0];
   assertNotEquals(null, titleElement);
   expectEquals(chrome.expectedTitle, titleElement.textContent);
 });