Add metadata to media::VideoFrame and plumb it through IPC/MediaStream.

content/browser/media/capture/content_video_capture_device_core.h

Index: content/browser/media/capture/content_video_capture_device_core.h
diff --git a/content/browser/media/capture/content_video_capture_device_core.h b/content/browser/media/capture/content_video_capture_device_core.h
index c86bb6c883aaea3a1e7eb7a9943366b2fb89a056..3f5588e5cb786e41bec9bd9c797aa020a0eb9599 100644
--- a/content/browser/media/capture/content_video_capture_device_core.h
+++ b/content/browser/media/capture/content_video_capture_device_core.h
@@ -92,6 +92,7 @@ class ThreadSafeCaptureOracle
   void DidCaptureFrame(
       int frame_number,
       const scoped_refptr<media::VideoCaptureDevice::Client::Buffer>& buffer,
+      base::TimeTicks capture_begin_time,
       const scoped_refptr<media::VideoFrame>& frame,
       base::TimeTicks timestamp,
       bool success);