Move media/audio files into media namespace (relanding)

media/audio/simple_sources.cc

Index: media/audio/simple_sources.cc
diff --git a/media/audio/simple_sources.cc b/media/audio/simple_sources.cc
index d2dc584a6eb752f68177d378e28f2d2c4a5d08c8..8b859619dd14b0e6d0e49ddf93e82a4191f82ebe 100644
--- a/media/audio/simple_sources.cc
+++ b/media/audio/simple_sources.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -13,6 +13,8 @@
 #include "media/audio/audio_io.h"
 #include "media/base/data_buffer.h"
 
+namespace media {
+
 //////////////////////////////////////////////////////////////////////////////
 // SineWaveAudioSource implementation.
 
@@ -96,3 +98,5 @@ void PushSource::ClearAll() {
 void PushSource::CleanUp() {
   buffer_.Clear();
 }
+
+}  // namespace media