Add gpu::MailboxHolder to hold state for a gpu::Mailbox

media/filters/gpu_video_decoder.h

Index: media/filters/gpu_video_decoder.h
diff --git a/media/filters/gpu_video_decoder.h b/media/filters/gpu_video_decoder.h
index 961e25ae3d9317205a1346f8baa69ecdce0a63a0..a7a8f368d21798fcba0ba4f05e524b57a378ec26 100644
--- a/media/filters/gpu_video_decoder.h
+++ b/media/filters/gpu_video_decoder.h
@@ -105,7 +105,8 @@ class MEDIA_EXPORT GpuVideoDecoder
       const scoped_refptr<VideoFrame>& frame);
 
   // Indicate the picture buffer can be reused by the decoder.
-  void ReusePictureBuffer(int64 picture_buffer_id, uint32 sync_point);
+  void ReusePictureBuffer(int64 picture_buffer_id,
+                          const gpu::MailboxHolder* mailbox_holder);
 
   void RecordBufferData(
       const BitstreamBuffer& bitstream_buffer, const DecoderBuffer& buffer);