Renderer side audio device change wip...

media/base/audio_renderer_mixer_input.h

Index: media/base/audio_renderer_mixer_input.h
diff --git a/media/base/audio_renderer_mixer_input.h b/media/base/audio_renderer_mixer_input.h
index a08b108c57d32ed9be5f2be2ef1f725b569ce26d..663c6137fc048f578c8aad2cbeb3dd097d6dcced 100644
--- a/media/base/audio_renderer_mixer_input.h
+++ b/media/base/audio_renderer_mixer_input.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/callback.h"
+#include "base/message_loop_proxy.h"
 #include "media/base/audio_converter.h"
 #include "media/base/audio_renderer_sink.h"
 
@@ -21,7 +22,7 @@ class MEDIA_EXPORT AudioRendererMixerInput
  public:
   typedef base::Callback<AudioRendererMixer*(
       const AudioParameters& params)> GetMixerCB;
-  typedef base::Callback<void(const AudioParameters& params)> RemoveMixerCB;
+  typedef base::Callback<void(AudioRendererMixer*)> RemoveMixerCB;
 
   AudioRendererMixerInput(
       const GetMixerCB& get_mixer_cb, const RemoveMixerCB& remove_mixer_cb);
@@ -43,6 +44,9 @@ class MEDIA_EXPORT AudioRendererMixerInput
   // Called by AudioRendererMixer when an error occurs.
   void OnRenderError();
 
+  // Called by AudioRendererMixer when a device change occurs.
+  void OnDeviceChange();
+
  protected:
   virtual ~AudioRendererMixerInput();
 
@@ -53,6 +57,8 @@ class MEDIA_EXPORT AudioRendererMixerInput
   bool initialized_;
   double volume_;
 
+  void UpdateMixer();
+
   // AudioConverter::InputCallback implementation.
   virtual double ProvideInput(AudioBus* audio_bus,
                               base::TimeDelta buffer_delay) OVERRIDE;
@@ -75,6 +81,9 @@ class MEDIA_EXPORT AudioRendererMixerInput
   // The current audio delay as last provided by AudioRendererMixer.
   int current_audio_delay_milliseconds_;
 
+  // The message loop of pipeline thread which started this input.
+  scoped_refptr<base::MessageLoopProxy> started_on_message_loop_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioRendererMixerInput);
 };