[Cast] VideoFrameFactory interface to vend frames with encoder affinity.

media/cast/cast_sender.h

Index: media/cast/cast_sender.h
diff --git a/media/cast/cast_sender.h b/media/cast/cast_sender.h
index 7615c28602c8f58052f4f7bf024c4eba79bc6bcc..8ac9f014ea0acf323626463cc99bc4e3cbd2b29a 100644
--- a/media/cast/cast_sender.h
+++ b/media/cast/cast_sender.h
@@ -36,6 +36,11 @@ class VideoFrameInput : public base::RefCountedThreadSafe<VideoFrameInput> {
       const scoped_refptr<media::VideoFrame>& video_frame,
       const base::TimeTicks& capture_time) = 0;
 
+  // Creates a |VideoFrame| suitable for input via |InsertRawVideoFrame|. Frames
+  // obtained in this manner may provide benefits such memory reuse and affinity
+  // with the encoder. The format is guaranteed to be I420 or NV12.
+  virtual scoped_refptr<VideoFrame> CreateFrame(base::TimeDelta timestamp) = 0;

[Alpha Left Google, 2014/11/19 19:22:18]

This looks good. What about adding the method bool ShouldCreateOptimizedFrame()
const? It can return true only if VideoFrameFactory is available. This way it is
clear that client should use this method to create or not.

+
  protected:
   virtual ~VideoFrameInput() {}