Implement VTTCue.region and sync the VTTRegion interface

third_party/WebKit/Source/core/html/track/InbandTextTrack.cpp

 /*
  * Copyright (C) 2012 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 79 matching lines @@
 
 void InbandTextTrack::addWebVTTCue(double start,
                                    double end,
                                    const WebString& id,
                                    const WebString& content,
                                    const WebString& settings) {
   HTMLMediaElement* owner = mediaElement();
   DCHECK(owner);
   VTTCue* cue = VTTCue::create(owner->document(), start, end, content);
   cue->setId(id);
-  cue->parseSettings(settings);
+  cue->parseSettings(nullptr, settings);
   addCue(cue);
 }
 
 }  // namespace blink