Fix ClearBrowserDataBrowserTest.CommitButtonDisabledWhileDeletionInProgress flake.

chrome/browser/ui/webui/options/options_ui_browsertest.cc

 // Copyright (c) 2012 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/options/options_ui_browsertest.h"
 
 #include "base/prefs/pref_service.h"
 #include "base/scoped_observer.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 112 matching lines @@
 
   // It is not possible to subscribe to the OnFinishedLoading event before the
   // call to NavigateToURL(), because the WebUI does not yet exist at that time.
   // However, it is safe to subscribe afterwards, because the event will always
   // be posted asynchronously to the message loop.
   scoped_refptr<MessageLoopRunner> message_loop_runner(new MessageLoopRunner);
   scoped_ptr<OptionsUI::OnFinishedLoadingCallbackList::Subscription>
       subscription = options_ui->RegisterOnFinishedLoadingCallback(
           message_loop_runner->QuitClosure());
   message_loop_runner->Run();
+
+  // The OnFinishedLoading event, which indicates that all WebUI initialization
+  // methods have been called on the JS side, is temporally unrelated to whether
+  // or not the WebContents considers itself to have finished loading. We want
+  // to wait for this too, however, because, e.g. this is a sufficient condition
+  // to get the focus properly placed on a form element.
+  content::WaitForLoadStop(web_contents);
 }
 
 void OptionsUIBrowserTest::NavigateToSettingsFrame() {
   const GURL& url = GURL(chrome::kChromeUISettingsFrameURL);
   ui_test_utils::NavigateToURL(browser(), url);
 }
 
 void OptionsUIBrowserTest::VerifyNavbar() {
   bool navbar_exist = false;
   EXPECT_TRUE(content::ExecuteScriptAndExtractBool(
@@ skipping 166 matching lines @@
   run_loop.Run();
 
   // Verify that the settings page has updated and lists two profiles.
   ASSERT_TRUE(content::ExecuteScriptAndExtractInt(
       contents, javascript, &profiles));
   EXPECT_EQ(2, profiles);
 }
 #endif
 
 }  // namespace options