Remove #pragma once. Just from base/ for now.

base/message_pump_android.h

 // 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.
 
 #ifndef BASE_MESSAGE_PUMP_ANDROID_H_
 #define BASE_MESSAGE_PUMP_ANDROID_H_
-#pragma once
 
 #include <jni.h>
 
 #include "base/compiler_specific.h"
 #include "base/message_pump.h"
 #include "base/time.h"
 
 namespace base {
 class RunLoop;
 
@@ skipping 17 matching lines @@
 
  private:
   base::RunLoop* run_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePumpForUI);
 };
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_PUMP_ANDROID_H_