Remove duplicated headers from core/

Source/core/platform/graphics/Font.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2010, 2011 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 10 matching lines @@
  *
  */
 
 #include "config.h"
 #include "core/platform/graphics/Font.h"
 
 #include "core/platform/graphics/WidthIterator.h"
 #include "platform/geometry/FloatRect.h"
 #include "platform/graphics/TextRun.h"
 #include "wtf/MainThread.h"
-#include "wtf/MathExtras.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/UnusedParam.h"
 #include "wtf/text/StringBuilder.h"
 
 using namespace WTF;
 using namespace Unicode;
 
 namespace WTF {
 
 // allow compilation of OwnPtr<TextLayout> in source files that don't have access to the TextLayout class definition
@@ skipping 648 matching lines @@
 }
 
 void Font::willUseFontData() const
 {
     const FontFamily& family = fontDescription().family();
     if (m_fontFallbackList && m_fontFallbackList->fontSelector() && !family.familyIsEmpty())
         m_fontFallbackList->fontSelector()->willUseFontData(fontDescription(), family.family());
 }
 
 }