// Add the new cue to a track, make sure it is inserted correctly.
        trackElement.track.addCue(textCue);
        assert_equals(textCue.track, trackElement.track);
        assert_equals(cues[1].startTime, 31);
        assert_equals(cues[2].startTime, 33);
        assert_equals(cues[3].startTime, 61);

        // create a new cue and add it to a track created with
        // video.addTextTrack, make sure it is inserted correctly.
        var newTrack = video.addTextTrack("subtitles", "French subtitles",