
PASS addTrack() with a track and no stream makes ontrack fire with a track and no stream.
PASS addTrack() with a track and a stream makes ontrack fire with a track and a stream.
PASS ontrack fires before setRemoteDescription resolves.
PASS addTrack() with two tracks and one stream makes ontrack fire twice with the tracks and shared stream.
PASS addTrack() for an existing stream makes stream.onaddtrack fire.
PASS stream.onaddtrack fires before setRemoteDescription resolves.
PASS addTrack() with a track and two streams makes ontrack fire with a track and two streams.
PASS ontrack's receiver matches getReceivers().
PASS removeTrack() does not remove the receiver.
PASS removeTrack() makes stream.onremovetrack fire and the track to be removed from the stream.
PASS stream.onremovetrack fires before setRemoteDescription resolves.
PASS removeTrack() makes track.onmute fire and the track to be muted.
PASS track.onmute fires before setRemoteDescription resolves.
PASS removeTrack() twice is safe.