Provide ability for WebUIBrowserTests to run asynchronous tests.

chrome/browser/ui/webui/web_ui_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 "chrome/browser/ui/webui/web_ui_browsertest.h"
 
 #include <string>
 #include <vector>
 
 #include "base/lazy_instance.h"
 #include "base/path_service.h"
@@ skipping 138 matching lines @@
   preload_test_name_ = preload_test_name;
 
   ui_test_utils::NavigateToURL(browser(), browse_to);
 
   TestTabStripModelObserver tabstrip_observer(
       browser()->tabstrip_model(), this);
   browser()->Print();
   tabstrip_observer.WaitForObservation();
 }
 
+bool WebUIBrowserTest::WaitForAsyncResult() {
+  return test_handler_->WaitForAsyncResult();
+}
+
 WebUIBrowserTest::WebUIBrowserTest()
     : test_handler_(new WebUITestHandler()),
       libraries_preloaded_(false) {}
 
 void WebUIBrowserTest::SetUpInProcessBrowserTestFixture() {
   ASSERT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &test_data_directory_));
   test_data_directory_ = test_data_directory_.Append(kWebUITestFolder);
 
   // TODO(dtseng): should this be part of every BrowserTest or just WebUI test.
   FilePath resources_pack_path;
@@ skipping 151 matching lines @@
 };
 
 WebUIBrowserTest* WebUIBrowserExpectFailTest::s_test_ = NULL;
 
 IN_PROC_BROWSER_TEST_F(WebUIBrowserExpectFailTest, TestFailsFast) {
   AddLibrary(FilePath(FILE_PATH_LITERAL("sample_downloads.js")));
   ui_test_utils::NavigateToURL(browser(), GURL(chrome::kChromeUIDownloadsURL));
   EXPECT_FATAL_FAILURE(RunJavascriptTestNoReturn("FAILS_BogusFunctionName"),
                        "WebUITestHandler::Observe");
 }