Split printing utility IPC messages into its own file.

chrome/utility/utility_message_handler.h

 // Copyright 2013 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 CHROME_UTILITY_UTILITY_MESSAGE_HANDLER_H_
 #define CHROME_UTILITY_UTILITY_MESSAGE_HANDLER_H_
 
 namespace IPC {
 class Message;
 }
 
-namespace chrome {
-
 class UtilityMessageHandler {
  public:
   virtual ~UtilityMessageHandler() {}
 
   // Called when a message is received.  Returns true iff the message was
   // handled.
   virtual bool OnMessageReceived(const IPC::Message& message) = 0;
 };
 
-}  // namespace chrome
-
 #endif  // CHROME_UTILITY_UTILITY_MESSAGE_HANDLER_H_