Bug 1057955: Adjust TrackUnion TrackID mapping to be 1:1 whenever possible with source tracks r=jesup
Bug 1057955: Support MediaStreamTrack.stop() r=roc,smaug
Bug 1057955: Stop the backend capture when the MSG track is stopped r=jib
Bug 1032839 - update RtpSender.track when replaceTrack succeeds r=jesup