Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/css/Counter.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 35 matching lines @@
 
     bool equals(const Counter& other) const
     {
         return identifier() == other.identifier()
             && listStyle() == other.listStyle()
             && separator() == other.separator();
     }
 
     PassRefPtrWillBeRawPtr<Counter> cloneForCSSOM() const
     {
-        return create(m_identifier ? m_identifier->cloneForCSSOM() : 0
-            , m_listStyle ? m_listStyle->cloneForCSSOM() : 0
-            , m_separator ? m_separator->cloneForCSSOM() : 0);
+        return create(m_identifier ? m_identifier->cloneForCSSOM() : nullptr
+            , m_listStyle ? m_listStyle->cloneForCSSOM() : nullptr
+            , m_separator ? m_separator->cloneForCSSOM() : nullptr);
     }
 
     void trace(Visitor*);
 
 private:
     Counter(PassRefPtrWillBeRawPtr<CSSPrimitiveValue> identifier, PassRefPtrWillBeRawPtr<CSSPrimitiveValue> listStyle, PassRefPtrWillBeRawPtr<CSSPrimitiveValue> separator)
         : m_identifier(identifier)
         , m_listStyle(listStyle)
         , m_separator(separator)
     {
     }
 
     RefPtrWillBeMember<CSSPrimitiveValue> m_identifier; // string
     RefPtrWillBeMember<CSSPrimitiveValue> m_listStyle; // ident
     RefPtrWillBeMember<CSSPrimitiveValue> m_separator; // string
 };
 
 } // namespace WebCore
 
 #endif // Counter_h