1. @DomName('TextTrackList.getTrackById')
  2. @DocsEditable()
  3. @Experimental()
TextTrack getTrackById(String id)

Source 

@DomName('TextTrackList.getTrackById')
@DocsEditable()
@Experimental() // untriaged
TextTrack getTrackById(String id) =>
    _blink.BlinkTextTrackList.instance.getTrackById_Callback_1_(this, id);