Remove "using namespace" statements from headers

Source/core/html/track/vtt/VTTParser.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:
  *
  *     * 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/Document.h"
 #include "core/dom/ProcessingInstruction.h"
 #include "core/dom/Text.h"
 #include "core/html/track/vtt/VTTElement.h"
 #include "core/html/track/vtt/VTTScanner.h"
 #include "platform/text/SegmentedString.h"
 #include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
+using namespace HTMLNames;
+
 const double secondsPerHour = 3600;
 const double secondsPerMinute = 60;
 const double secondsPerMillisecond = 0.001;
 const unsigned fileIdentifierLength = 6;
 
 static unsigned scanDigits(const String& input, unsigned* position)
 {
     unsigned startPosition = *position;
     while (*position < input.length() && isASCIIDigit(input[*position]))
         (*position)++;
@@ skipping 535 matching lines @@
             m_currentNode->parserAppendChild(ProcessingInstruction::create(document, "timestamp", charactersString));
         break;
     }
     default:
         break;
     }
 }
 
 }