InbandTextTrack::willRemoveTextTrackPrivate may be called after the owning HTMLMediaElement has been cleared because the media engine and the media element do not operate in sync. In this case, the media element has already dealt with the track removal so the notification from the media engine is not needed.
Created attachment 205302 [details]
Comment on attachment 205302 [details]
Null checks ftw! r=me.