Allow WebUI Tests to use preLoad in HtmlDialogUI.

chrome/test/data/webui/print_preview.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 print preview WebUI testing.
  * @extends {testing.Test}
  * @constructor
  */
 function PrintPreviewWebUITest() {}
@@ skipping 145 matching lines @@
 
   /**
    * Always return true so tests run on systems without plugin available.
    * @return {boolean} Always true.
    */
   checkCompatiblePluginExists: function() {
     return true;
   },
 };
 
-GEN('#include "base/command_line.h"');
-GEN('#include "chrome/browser/ui/webui/web_ui_browsertest.h"');
-GEN('#include "chrome/common/chrome_switches.h"');
-GEN('');
-GEN('class PrintPreviewWebUITest');
-GEN('    : public WebUIBrowserTest {');
-GEN(' protected:');
-GEN('  // WebUIBrowserTest override.');
-GEN('  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {');
-GEN('    WebUIBrowserTest::SetUpCommandLine(command_line);');
-GEN('    command_line->AppendSwitch(switches::kEnablePrintPreview);');
-GEN('  }');
-GEN('');
-GEN('};');
-GEN('');
+GEN('#include "chrome/test/data/webui/print_preview.h"');
 
 /**
  * The expected length of the |printer-list| element.
  * @type {number}
  * @const
  */
 var printerListMinLength = 2;
 
 /**
  * The expected index of the "foo" printer returned by the stubbed handler.
@@ skipping 222 matching lines @@
 
 // Test that error message is displayed when plugin doesn't exist.
 TEST_F('PrintPreviewNoPDFWebUITest', 'TestErrorMessage', function() {
   var errorButton = $('error-button');
   assertNotEquals(null, errorButton);
   expectFalse(errorButton.disabled);
   var errorText = $('custom-message');
   assertNotEquals(null, errorText);
   expectFalse(errorText.hidden);
 });