     assert_equals(cues[1].startTime, 31);
        assert_equals(cues[2].startTime, 121);

        // Try to remove the cue again.
        assert_throws_dom("NotFoundError", function() { trackElement.track.removeCue(textCue); });

        // Add a cue before all the existing cues.
        trackElement.track.addCue(new VTTCue(0, 31, "I am first"));
        assert_equals(cues[0].startTime, 0);
        assert_equals(cues[0].endTime, 31);
        assert_equals(cues[1].startTime, 0);
        assert_equals(cues[1