Reland: Add Stop() to AudioDecoder. (https://codereview.chromium.org/126793002/)

media/filters/ffmpeg_audio_decoder.h

Index: media/filters/ffmpeg_audio_decoder.h
diff --git a/media/filters/ffmpeg_audio_decoder.h b/media/filters/ffmpeg_audio_decoder.h
index d143433daa6df38d56fbbce6734e2bc1f29d8e9b..42bce45109ab5a5b82d2002a0356dac5fdc6660e 100644
--- a/media/filters/ffmpeg_audio_decoder.h
+++ b/media/filters/ffmpeg_audio_decoder.h
@@ -45,6 +45,7 @@ class MEDIA_EXPORT FFmpegAudioDecoder : public AudioDecoder {
   virtual ChannelLayout channel_layout() OVERRIDE;
   virtual int samples_per_second() OVERRIDE;
   virtual void Reset(const base::Closure& closure) OVERRIDE;
+  virtual void Stop(const base::Closure& closure) OVERRIDE;
 
   // Callback called from within FFmpeg to allocate a buffer based on
   // the dimensions of |codec_context|. See AVCodecContext.get_buffer2
@@ -52,6 +53,9 @@ class MEDIA_EXPORT FFmpegAudioDecoder : public AudioDecoder {
   int GetAudioBuffer(AVCodecContext* codec, AVFrame* frame, int flags);
 
  private:
+  void DoStop();
+  void DoReset();
+
   // Reads from the demuxer stream with corresponding callback method.
   void ReadFromDemuxerStream();
   void BufferReady(DemuxerStream::Status status,
@@ -92,6 +96,8 @@ class MEDIA_EXPORT FFmpegAudioDecoder : public AudioDecoder {
   scoped_ptr_malloc<AVFrame, ScopedPtrAVFreeFrame> av_frame_;
 
   ReadCB read_cb_;
+  base::Closure stop_cb_;
+  base::Closure reset_cb_;
 
   // Since multiple frames may be decoded from the same packet we need to queue
   // them up and hand them out as we receive Read() calls.