Add base::RunLoop and update ui_test_utils to use it to reduce flakiness

chrome/browser/tab_contents/render_view_context_menu_browsertest_util.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/tab_contents/render_view_context_menu_browsertest_util.h"
 
 #include "base/message_loop.h"
 #include "base/bind.h"
 #include "chrome/browser/tab_contents/render_view_context_menu.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/notification_service.h"
 
 ContextMenuNotificationObserver::ContextMenuNotificationObserver(
-    int command_to_execute,
-    int expected_notification)
-    : command_to_execute_(command_to_execute),
-      expected_notification_(expected_notification),
-      seen_expected_notification_(false) {
+    int command_to_execute)
+    : command_to_execute_(command_to_execute) {
   registrar_.Add(this,
                  chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_SHOWN,
                  content::NotificationService::AllSources());
-  registrar_.Add(this,
-                 chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_CLOSED,
-                 content::NotificationService::AllSources());
-  registrar_.Add(this,
-                 expected_notification_,
-                 content::NotificationService::AllSources());
 }
 
 ContextMenuNotificationObserver::~ContextMenuNotificationObserver() {
 }
 
 void ContextMenuNotificationObserver::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
-  if (type == expected_notification_) {
-    seen_expected_notification_ = true;
-    return;
-  }
-
   switch (type) {
     case chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_SHOWN: {
       RenderViewContextMenu* context_menu =
           content::Source<RenderViewContextMenu>(source).ptr();
       MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(&ContextMenuNotificationObserver::ExecuteCommand,
                      base::Unretained(this), context_menu));
       break;
     }
-    case chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_CLOSED: {
-      // Aura is running a nested message loop for menus. That means that
-      // whatever the test running us is waiting for (e.g. a new tab to be
-      // added) happened while the menu message loop was running, so the
-      // message loop run by this test never quits.
-      if (seen_expected_notification_ &&
-          MessageLoop::current()->is_running()) {
-        MessageLoop::current()->QuitNow();
-      }
-      break;
-    }
 
     default:
       NOTREACHED();
   }
 }
 
 void ContextMenuNotificationObserver::ExecuteCommand(
     RenderViewContextMenu* context_menu) {
   context_menu->ExecuteCommand(command_to_execute_);
   context_menu->Cancel();
 }