media: Add support for playback of VP8 Alpha video streams

media/filters/vpx_video_decoder.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_FILTERS_VPX_VIDEO_DECODER_H_
 #define MEDIA_FILTERS_VPX_VIDEO_DECODER_H_
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/video_decoder.h"
+#include "media/base/video_frame.h"
 
 struct vpx_codec_ctx;
 struct vpx_image;
 
 namespace base {
 class MessageLoopProxy;
 }
 
 namespace media {
 
@@ skipping 32 matching lines @@
                                const scoped_refptr<DecoderBuffer>& buffer);
 
   void DecodeBuffer(const scoped_refptr<DecoderBuffer>& buffer);
   bool Decode(const scoped_refptr<DecoderBuffer>& buffer,
               scoped_refptr<VideoFrame>* video_frame);
 
   // Reset decoder and call |reset_cb_|.
   void DoReset();
 
   void CopyVpxImageTo(const vpx_image* vpx_image,
+                      const struct vpx_image* vpx_image_alpha,
                       scoped_refptr<VideoFrame>* video_frame);
 
   scoped_refptr<base::MessageLoopProxy> message_loop_;
   base::WeakPtrFactory<VpxVideoDecoder> weak_factory_;
   base::WeakPtr<VpxVideoDecoder> weak_this_;
 
   DecoderState state_;
 
   StatisticsCB statistics_cb_;
   ReadCB read_cb_;
   base::Closure reset_cb_;
 
   // Pointer to the demuxer stream that will feed us compressed buffers.
   scoped_refptr<DemuxerStream> demuxer_stream_;
 
   vpx_codec_ctx* vpx_codec_;
+  vpx_codec_ctx* vpx_codec_alpha_;
 
   DISALLOW_COPY_AND_ASSIGN(VpxVideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_VPX_VIDEO_DECODER_H_