Move media/audio files into media namespace

media/audio/audio_manager.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 "media/audio/audio_manager.h"
 
 #include "base/at_exit.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 
+namespace media {
+
 // Forward declaration of the platform specific AudioManager factory function.
 AudioManager* CreateAudioManager();
 
 AudioManager::AudioManager() {
 }
 
 AudioManager::~AudioManager() {
 }
 
 // static
 AudioManager* AudioManager::Create() {
   AudioManager* ret = CreateAudioManager();
   ret->Init();
   return ret;
 }
+
+}  // namespace media