Tests that the cue display tree has been removed properly and no crash happens.

** Set the mode of the text track to showing **

** Initialize the video element **
EVENT(canplaythrough)

** Empty the contents of the video element when it is ready to play **

** Text track should not be rendered anymore **
No text track cue with display id '-webkit-media-text-track-display' is currently visible

No crash. PASS.

END OF TEST

