Document that preferred VideoFrame constructor takes no RTP timestamp.

And update most internal calls to use it.

Bug: webrtc:5740, webrtc:9372
Change-Id: Ib57d4ebfa7b0729af6d22981a792f0fdadf8a13f
Reviewed-on: https://webrtc-review.googlesource.com/81743
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23567}
diff --git a/api/video/video_frame.h b/api/video/video_frame.h
index a72bef1..bd54820 100644
--- a/api/video/video_frame.h
+++ b/api/video/video_frame.h
@@ -20,16 +20,14 @@
 
 class VideoFrame {
  public:
-  // TODO(nisse): This constructor is consistent with the now deleted
-  // cricket::WebRtcVideoFrame. We should consider whether or not we
-  // want to stick to this style and deprecate the other constructor.
+  // Preferred constructor.
   VideoFrame(const rtc::scoped_refptr<VideoFrameBuffer>& buffer,
              webrtc::VideoRotation rotation,
              int64_t timestamp_us);
 
-  // Preferred constructor.
+  // For use by the parts of the pipeline that needs the RTP 90kHz timestamp.
   VideoFrame(const rtc::scoped_refptr<VideoFrameBuffer>& buffer,
-             uint32_t timestamp,
+             uint32_t timestamp_rtp,
              int64_t render_time_ms,
              VideoRotation rotation);