Remove "using namespace" statements from headers

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 14 matching lines @@
 
 #include "config.h"
 #include "core/html/track/LoadableTextTrack.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(), track, emptyAtom, emptyAtom, emptyAtom, emptyAtom, TrackElement)
     , m_trackElement(track)
     , m_loadTimer(this, &LoadableTextTrack::loadTimerFired)
     , m_isDefault(false)
 {
 }
 
 LoadableTextTrack::~LoadableTextTrack()
 {
@@ skipping 103 matching lines @@
             return index;
         ++index;
     }
     ASSERT_NOT_REACHED();
 
     return 0;
 }
 
 } // namespace WebCore