Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/rendering/style/NinePieceImage.cpp

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008, 2013 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 37 matching lines @@
     m_data.access()->outset = outset;
     m_data.access()->fill = fill;
     m_data.access()->horizontalRule = horizontalRule;
     m_data.access()->verticalRule = verticalRule;
 }
 
 NinePieceImageData::NinePieceImageData()
     : fill(false)
     , horizontalRule(StretchImageRule)
     , verticalRule(StretchImageRule)
-    , image(0)
+    , image(nullptr)
     , imageSlices(Length(100, Percent), Length(100, Percent), Length(100, Percent), Length(100, Percent))
     , borderSlices(1.0, 1.0, 1.0, 1.0)
     , outset(Length(0, Fixed), Length(0, Fixed), Length(0, Fixed), Length(0, Fixed))
 {
 }
 
 NinePieceImageData::NinePieceImageData(const NinePieceImageData& other)
     : RefCounted<NinePieceImageData>()
     , fill(other.fill)
     , horizontalRule(other.horizontalRule)
@@ skipping 10 matching lines @@
     return StyleImage::imagesEquivalent(image.get(), other.image.get())
         && imageSlices == other.imageSlices
         && fill == other.fill
         && borderSlices == other.borderSlices
         && outset == other.outset
         && horizontalRule == other.horizontalRule
         && verticalRule == other.verticalRule;
 }
 
 }