Tab Capture: Backing store readbacks to YV12 VideoFrames.

content/port/browser/render_widget_host_view_port.h

Index: content/port/browser/render_widget_host_view_port.h
diff --git a/content/port/browser/render_widget_host_view_port.h b/content/port/browser/render_widget_host_view_port.h
index 953296c0b4a9035cc7e89387c5d553d5ea9e087e..92fca5c081889308e7ed8806b5743ec82a25795d 100644
--- a/content/port/browser/render_widget_host_view_port.h
+++ b/content/port/browser/render_widget_host_view_port.h
@@ -25,6 +25,10 @@ struct GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params;
 struct GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params;
 struct ViewHostMsg_TextInputState_Params;
 
+namespace media {
+class VideoFrame;
+}
+
 namespace webkit {
 namespace npapi {
 struct WebPluginGeometry;
@@ -163,6 +167,13 @@ class CONTENT_EXPORT RenderWidgetHostViewPort : public RenderWidgetHostView {
       const gfx::Size& dst_size,
       const base::Callback<void(bool, const SkBitmap&)>& callback) = 0;
 
+#if defined(OS_WIN)
+  virtual void CopyFromCompositingSurfaceToVideoFrame(
+      const gfx::Rect& src_subrect,
+      const gfx::Size& dst_size,
+      const base::Callback<void(media::VideoFrame*)>& callback) = 0;
+#endif
+
   // Called when accelerated compositing state changes.
   virtual void OnAcceleratedCompositingStateChange() = 0;
   // |params.window| and |params.surface_id| indicate which accelerated