media: Add MojoDecoderBuffer{Reader|Writer}

media/mojo/services/mojo_video_decoder_service.h

Index: media/mojo/services/mojo_video_decoder_service.h
diff --git a/media/mojo/services/mojo_video_decoder_service.h b/media/mojo/services/mojo_video_decoder_service.h
index 7101a372b8b47232a86658e0b8a3a2a08dd716c1..f0338ce2eddc9992797489e3390ce30ac7759bce 100644
--- a/media/mojo/services/mojo_video_decoder_service.h
+++ b/media/mojo/services/mojo_video_decoder_service.h
@@ -12,10 +12,10 @@
 #include "media/base/decode_status.h"
 #include "media/mojo/interfaces/video_decoder.mojom.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
-#include "mojo/public/cpp/system/data_pipe.h"
 
 namespace media {
 
+class MojoDecoderBufferReader;
 class MojoMediaClient;
 class VideoDecoder;
 class VideoFrame;
@@ -46,7 +46,7 @@ class MojoVideoDecoderService : public mojom::VideoDecoder {
 
   mojo::StrongBinding<mojom::VideoDecoder> binding_;
   mojom::VideoDecoderClientPtr client_;
-  mojo::ScopedDataPipeConsumerHandle decoder_buffer_pipe_;
+  std::unique_ptr<MojoDecoderBufferReader> mojo_decoder_buffer_reader_;
 
   MojoMediaClient* mojo_media_client_;
   std::unique_ptr<media::VideoDecoder> decoder_;