Put the Pepper stuff in the content namespace.

content/renderer/pepper/pepper_platform_audio_output_impl.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 CONTENT_RENDERER_PEPPER_PEPPER_PLATFORM_AUDIO_OUTPUT_IMPL_H_
 #define CONTENT_RENDERER_PEPPER_PEPPER_PLATFORM_AUDIO_OUTPUT_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "content/renderer/media/audio_message_filter.h"
 #include "webkit/plugins/ppapi/plugin_delegate.h"
 
 class AudioParameters;
 
 namespace base {
 class MessageLoopProxy;
 }
 
+namespace content {
+
 class PepperPlatformAudioOutputImpl
     : public webkit::ppapi::PluginDelegate::PlatformAudioOutput,
       public AudioMessageFilter::Delegate,
       public base::RefCountedThreadSafe<PepperPlatformAudioOutputImpl> {
  public:
   virtual ~PepperPlatformAudioOutputImpl();
 
   // Factory function, returns NULL on failure. StreamCreated() will be called
   // when the stream is created.
   static PepperPlatformAudioOutputImpl* Create(
@@ skipping 36 matching lines @@
 
   // Our ID on the MessageFilter. THIS MUST ONLY BE ACCESSED ON THE I/O THREAD
   // or else you could race with the initialize function which sets it.
   int32 stream_id_;
 
   base::MessageLoopProxy* main_message_loop_proxy_;
 
   DISALLOW_COPY_AND_ASSIGN(PepperPlatformAudioOutputImpl);
 };
 
+}  // namespace content
+
 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_PLATFORM_AUDIO_OUTPUT_IMPL_H_