[PPAPI] Pepper MediaStream API audio track implementation and example.

ppapi/thunk/ppb_audio_frame_api.h

Index: ppapi/thunk/ppb_audio_frame_api.h
diff --git a/ppapi/thunk/ppb_audio_frame_api.h b/ppapi/thunk/ppb_audio_frame_api.h
index 21c4d7146358e73f2824a3464fd7ff771e49417c..ca9cd1f6602bb1cc36ce8fc5d0c2a8687ac204a8 100644
--- a/ppapi/thunk/ppb_audio_frame_api.h
+++ b/ppapi/thunk/ppb_audio_frame_api.h
@@ -9,6 +9,9 @@
 #include "ppapi/thunk/ppapi_thunk_export.h"
 
 namespace ppapi {
+
+union MediaStreamFrame;
+
 namespace thunk {
 
 class PPAPI_THUNK_EXPORT PPB_AudioFrame_API {
@@ -16,11 +19,17 @@ class PPAPI_THUNK_EXPORT PPB_AudioFrame_API {
   virtual ~PPB_AudioFrame_API() {}
   virtual PP_TimeDelta GetTimestamp() = 0;
   virtual void SetTimestamp(PP_TimeDelta timestamp) = 0;
+  virtual PP_AudioFrame_SampleRate GetSampleRate() = 0;
   virtual PP_AudioFrame_SampleSize GetSampleSize() = 0;
   virtual uint32_t GetNumberOfChannels() = 0;
   virtual uint32_t GetNumberOfSamples() = 0;
   virtual void* GetDataBuffer() = 0;
   virtual uint32_t GetDataBufferSize() = 0;
+
+  // Methods used by Pepper internal implementation only.
+  virtual MediaStreamFrame* GetFrameBuffer() = 0;
+  virtual int32_t GetFrameBufferIndex() = 0;
+  virtual void Invalidate() = 0;
 };
 
 }  // namespace thunk