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

base/message_pump_android.h

 // 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.
 
 #ifndef BASE_MESSAGE_PUMP_ANDROID_H_
 #define BASE_MESSAGE_PUMP_ANDROID_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
@@ skipping 10 matching lines @@
   virtual ~MessagePumpForUI();
 
   virtual void Run(Delegate* delegate) OVERRIDE;
   virtual void Quit() OVERRIDE;
   virtual void ScheduleWork() OVERRIDE;
   virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) OVERRIDE;
 
   virtual void Start(Delegate* delegate);
 
  private:
-  MessageLoop::AutoRunState* state_;
+  MessageLoop::RunLoop* run_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePumpForUI);
 };
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_PUMP_ANDROID_H_