Add an additional VDA::Flush() mode to return all allocated buffers.

media/video/video_decode_accelerator.h

Index: media/video/video_decode_accelerator.h
diff --git a/media/video/video_decode_accelerator.h b/media/video/video_decode_accelerator.h
index c0f6b1e862b8d78cbe4f932f98ca1514a5a064e0..e226bc28f79cc983dd8b3463abe7b9b953bfb772 100644
--- a/media/video/video_decode_accelerator.h
+++ b/media/video/video_decode_accelerator.h
@@ -207,8 +207,12 @@ class MEDIA_EXPORT VideoDecodeAccelerator {
 
   // Flushes the decoder: all pending inputs will be decoded and pictures handed
   // back to the client, followed by NotifyFlushDone() being called on the
-  // client.  Can be used to implement "end of stream" notification.
-  virtual void Flush() = 0;
+  // client. If |return_buffers| is true, VDA must return all PictureBuffers it

[kcwu, 2016/03/22 09:47:42]

s/return all PictureBuffers/return all PictureBuffers via PictureReady/

+  // owns, not only ones containing pictures remaining in the decoder at the
+  // time of this call. To indicate a returned buffer does not contain a decoded
+  // frame, the VDA must set bitstream_buffer_id = -1 in the returned Picture.
+  // Can be used to implement "end of stream" notification.
+  virtual void Flush(bool return_buffers) = 0;

[kcwu, 2016/03/22 09:47:42]

How about move the description of |return_buffers| to after 'Can be used to
implement "end of stream" notification.' or into separate "Parameters:" section?
Otherwise I was confused that 'Can be used to implement "end of stream"
notification.' is related to |return_buffers|.

 
   // Resets the decoder: all pending inputs are dropped immediately and the
   // decoder returned to a state ready for further Decode()s, followed by