Ensure that a TextTrack won't be collected if it has a custom property.

** Validate.
EXPECTED (video.textTracks.length == '1') OK
EXPECTED (video.textTracks[0].kind == 'captions') OK

** Add a custom property to the track.
RUN(video.textTracks[0].myProperty = 'egg salad!?')
EXPECTED (video.textTracks[0].myProperty == 'egg salad!?') OK

** Force garbage collection.
EXPECTED (video.textTracks[0].cues.length == '4') OK
EXPECTED (video.textTracks[0].myProperty == 'egg salad!?') OK

END OF TEST

