Add TODO comments on deprecated VideoFrame methods.

webrtc/media/engine/webrtcvideoframe.h

Index: webrtc/media/engine/webrtcvideoframe.h
diff --git a/webrtc/media/engine/webrtcvideoframe.h b/webrtc/media/engine/webrtcvideoframe.h
index 487e32ef9af23630f749f65dca93558d80555eef..d652f1baef4b59931a5574edcdd68ab2df29006c 100644
--- a/webrtc/media/engine/webrtcvideoframe.h
+++ b/webrtc/media/engine/webrtcvideoframe.h
@@ -24,16 +24,22 @@ namespace cricket {
 
 struct CapturedFrame;
 
+// TODO(nisse): This class will be deleted when the cricket::VideoFrame and
+// webrtc::VideoFrame classes are merged. See
+// https://bugs.chromium.org/p/webrtc/issues/detail?id=5682. Try to use only the
+// preferred constructor, and the non-deprecated methods of the VideoFrame base
+// class.
 class WebRtcVideoFrame : public VideoFrame {
  public:
   WebRtcVideoFrame();
 
-  // Preferred construction, with microsecond timestamp.
+  // Preferred constructor.
   WebRtcVideoFrame(const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& buffer,
                    webrtc::VideoRotation rotation,
                    int64_t timestamp_us);
 
-  // TODO(nisse): Deprecate/delete.
+  // TODO(nisse): Deprecated, delete as soon as all callers have switched to the
+  // above constructor with microsecond timestamp.
   WebRtcVideoFrame(const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& buffer,
                    int64_t time_stamp_ns,
                    webrtc::VideoRotation rotation);