Add callback in VideoDecoder and AudioDecoder to return decoded frames.

media/filters/ffmpeg_video_decoder.h

Index: media/filters/ffmpeg_video_decoder.h
diff --git a/media/filters/ffmpeg_video_decoder.h b/media/filters/ffmpeg_video_decoder.h
index c8481a24f92229b53459e76e59ede5f6d797699e..dc1be68b90c2147c704fe5dc4a7a166c9e7c658e 100644
--- a/media/filters/ffmpeg_video_decoder.h
+++ b/media/filters/ffmpeg_video_decoder.h
@@ -34,7 +34,8 @@ class MEDIA_EXPORT FFmpegVideoDecoder : public VideoDecoder {
   // VideoDecoder implementation.
   virtual void Initialize(const VideoDecoderConfig& config,
                           bool low_delay,
-                          const PipelineStatusCB& status_cb) OVERRIDE;
+                          const PipelineStatusCB& status_cb,
+                          const OutputCB& output_cb) OVERRIDE;
   virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
                       const DecodeCB& decode_cb) OVERRIDE;
   virtual void Reset(const base::Closure& closure) OVERRIDE;
@@ -49,13 +50,11 @@ class MEDIA_EXPORT FFmpegVideoDecoder : public VideoDecoder {
   enum DecoderState {
     kUninitialized,
     kNormal,
-    kFlushCodec,
     kDecodeFinished,
     kError
   };
 
   // Handles decoding an unencrypted encoded buffer.
-  void DecodeBuffer(const scoped_refptr<DecoderBuffer>& buffer);
   bool FFmpegDecode(const scoped_refptr<DecoderBuffer>& buffer,
                     scoped_refptr<VideoFrame>* video_frame);
 
@@ -71,8 +70,7 @@ class MEDIA_EXPORT FFmpegVideoDecoder : public VideoDecoder {
 
   DecoderState state_;
 
-  // TODO(xhwang): Merge DecodeBuffer() into Decode() and remove this.
-  DecodeCB decode_cb_;
+  OutputCB output_cb_;
 
   // FFmpeg structures owned by this object.
   scoped_ptr<AVCodecContext, ScopedPtrAVFreeContext> codec_context_;