Add MediaCodecAudioDecoder implementation

media/base/audio_buffer.h

Index: media/base/audio_buffer.h
diff --git a/media/base/audio_buffer.h b/media/base/audio_buffer.h
index 8ae281eabda8788e53985f7c8f684e884e0594f8..1b40754cbc4e2e99ecdc8ed2c0859fbf2d8e4499 100644
--- a/media/base/audio_buffer.h
+++ b/media/base/audio_buffer.h
@@ -131,10 +131,16 @@ class MEDIA_EXPORT AudioBuffer
   // If there's no data in this buffer, it represents end of stream.
   bool end_of_stream() const { return end_of_stream_; }
 
-  // Access to the raw buffer for ffmpeg to write directly to. Data for planar
-  // data is grouped by channel. There is only 1 entry for interleaved formats.
+  // Access to the raw buffer for ffmpeg and Android MediaCodec decoders to
+  // write directly to. For planar formats the vector elements correspond to
+  // the channels. For interleaved formats the resulting vector has exactly
+  // one element which contains the buffer pointer.
   const std::vector<uint8_t*>& channel_data() const { return channel_data_; }
 
+  // The size of allocated data memory block. For planar formats channels go
+  // sequentially in this block.
+  size_t data_size() const { return data_size_; }
+
  private:
   friend class base::RefCountedThreadSafe<AudioBuffer>;