Remove the unused Document& argument to the TextTrack constructor

Source/core/html/track/LoadableTextTrack.cpp

 /*
  * Copyright (C) 2011 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:
  * 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 19 matching lines @@
 #include "core/html/HTMLMediaElement.h"
 #include "core/html/HTMLTrackElement.h"
 #include "core/html/track/TextTrackCueList.h"
 #include "core/html/track/vtt/VTTRegionList.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
 
 LoadableTextTrack::LoadableTextTrack(HTMLTrackElement* track)
-    : TextTrack(track->document(), emptyAtom, emptyAtom, emptyAtom, emptyAtom, TrackElement)
+    : TextTrack(emptyAtom, emptyAtom, emptyAtom, emptyAtom, TrackElement)
     , m_trackElement(track)
     , m_loadTimer(this, &LoadableTextTrack::loadTimerFired)
     , m_isDefault(false)
 {
 }
 
 LoadableTextTrack::~LoadableTextTrack()
 {
 #if !ENABLE(OILPAN)
     ASSERT(!m_trackElement);
@@ skipping 121 matching lines @@
 }
 
 void LoadableTextTrack::trace(Visitor* visitor)
 {
     visitor->trace(m_trackElement);
     visitor->trace(m_loader);
     TextTrack::trace(visitor);
 }
 
 } // namespace WebCore