[Mojo Video Capture] Split OnIncomingCapturedVideoFrame() to OnNewBuffer() and OnFrameReadyInBuffer(

content/browser/renderer_host/media/video_capture_controller_event_handler.h

Index: content/browser/renderer_host/media/video_capture_controller_event_handler.h
diff --git a/content/browser/renderer_host/media/video_capture_controller_event_handler.h b/content/browser/renderer_host/media/video_capture_controller_event_handler.h
index b8a8a82bdf3884d44b2a658c39ea15bac083008a..668cad5bf366639a89d8987e51a0a1a90be8bd2f 100644
--- a/content/browser/renderer_host/media/video_capture_controller_event_handler.h
+++ b/content/browser/renderer_host/media/video_capture_controller_event_handler.h
@@ -9,6 +9,7 @@
 
 #include "base/memory/shared_memory.h"
 #include "content/common/content_export.h"
+#include "content/common/video_capture.mojom.h"
 #include "mojo/public/cpp/system/buffer.h"
 #include "ui/gfx/geometry/size.h"
 
@@ -42,7 +43,7 @@ class CONTENT_EXPORT VideoCaptureControllerEventHandler {
   // A buffer has been filled with a captured VideoFrame.
   virtual void OnBufferReady(VideoCaptureControllerID id,
                              int buffer_id,
-                             const scoped_refptr<media::VideoFrame>& frame) = 0;
+                             media::mojom::VideoFrameInfoPtr frame_info) = 0;

[miu, 2017/02/14 00:41:27]

Sanity-check: This new argument transfers ownership of the VideoFrameInfo. Is
that better than just providing a read-only "const VideoFrameInfo&"? Personally,
I lean toward whichever interface results in fewer memcpy's.

[chfremer, 2017/02/14 21:15:16]

Yes. Transfer of ownership was intended here.
Not sure if it is better than passing a const reference, though.
Someone, either the caller (VideoCaptureController) or the receiver
(VideoCaptureHost) of the method has to make a copy of |frame_info|. It doesn't
really matter which side does the cloning. My thought was to let
VideoCapturecontroller do the cloning, since it has the responsibility of
"broadcasting" the frame to multiple clients. But since VideoCaptureHost may
decide to just drop the frame, I guess we could (in edge cases) avoid
unnecessary copies if we let VideoCaptureHost do the cloning.

Done.

 
   // The capture session has ended and no more frames will be sent.
   virtual void OnEnded(VideoCaptureControllerID id) = 0;