Allow WebUI Tests to use preLoad in HtmlDialogUI.

chrome/browser/errorpage_browsertest.cc

 // 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.
 
 #include "base/bind.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/net/url_request_mock_util.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/test_navigation_observer.h"
 #include "chrome/test/base/ui_test_utils.h"
-#include "chrome/test/test_navigation_observer.h"
 #include "content/browser/net/url_request_failed_dns_job.h"
 #include "content/browser/net/url_request_mock_http_job.h"
 
 using content::BrowserThread;
 
 class ErrorPageTest : public InProcessBrowserTest {
  public:
   enum HistoryNavigationDirection {
     HISTORY_NAVIGATE_BACK,
     HISTORY_NAVIGATE_FORWARD,
@@ skipping 162 matching lines @@
 }
 
 // Checks that the Link Doctor is not loaded when we receive an actual 404 page.
 IN_PROC_BROWSER_TEST_F(ErrorPageTest, Page404) {
   NavigateToURLAndWaitForTitle(
       URLRequestMockHTTPJob::GetMockUrl(
           FilePath(FILE_PATH_LITERAL("page404.html"))),
       "SUCCESS",
       1);
 }