Remove the unused Document& argument to the TextTrack constructor

Source/core/html/track/vtt/VTTRegion.h

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 23 matching lines @@
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/html/track/TextTrack.h"
 #include "platform/Timer.h"
 #include "platform/geometry/FloatPoint.h"
 #include "platform/heap/Handle.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/RefCounted.h"
 
 namespace WebCore {
 
+class Document;
 class ExceptionState;
 class HTMLDivElement;
 class VTTCueBox;
 class VTTScanner;
 
 class VTTRegion FINAL : public RefCountedWillBeGarbageCollectedFinalized<VTTRegion> {
 public:
     static PassRefPtrWillBeRawPtr<VTTRegion> create()
     {
         return adoptRefWillBeNoop(new VTTRegion());
@@ skipping 94 matching lines @@
     // The timer is used to display the next cue line after the current one has
     // been displayed. It's main use is for scrolling regions and it triggers as
     // soon as the animation for rolling out one line has finished, but
     // currently it is used also for non-scrolling regions to use a single
     // code path.
     Timer<VTTRegion> m_scrollTimer;
 };
 
 } // namespace WebCore
 #endif