Remove duplicated headers from core/

Source/core/timing/PerformanceUserTiming.cpp

 /*
  * Copyright (C) 2012 Intel 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/timing/PerformanceUserTiming.h"
 
 #include "bindings/v8/ExceptionState.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/timing/Performance.h"
 #include "core/timing/PerformanceMark.h"
 #include "core/timing/PerformanceMeasure.h"
 #include "public/platform/Platform.h"
-#include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
 namespace {
 
 typedef HashMap<String, NavigationTimingFunction> RestrictedKeyMap;
 static RestrictedKeyMap restrictedKeyMap()
 {
     DEFINE_STATIC_LOCAL(RestrictedKeyMap, map, ());
     if (map.isEmpty()) {
@@ skipping 154 matching lines @@
 {
     return convertToEntrySequence(m_measuresMap);
 }
 
 Vector<RefPtr<PerformanceEntry> > UserTiming::getMeasures(const String& name) const
 {
     return getEntrySequenceByName(m_measuresMap, name);
 }
 
 } // namespace WebCore