Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/dom/ElementData.cpp

 /*
  * Copyright (C) 2013 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 168 matching lines @@
 
 UniqueElementData::UniqueElementData()
 {
 }
 
 UniqueElementData::UniqueElementData(const UniqueElementData& other)
     : ElementData(other, true)
     , m_presentationAttributeStyle(other.m_presentationAttributeStyle)
     , m_attributeVector(other.m_attributeVector)
 {
-    m_inlineStyle = other.m_inlineStyle ? other.m_inlineStyle->mutableCopy() : 0;
+    m_inlineStyle = other.m_inlineStyle ? other.m_inlineStyle->mutableCopy() : nullptr;
 }
 
 UniqueElementData::UniqueElementData(const ShareableElementData& other)
     : ElementData(other, true)
 {
     // An ShareableElementData should never have a mutable inline StylePropertySet attached.
     ASSERT(!other.m_inlineStyle || !other.m_inlineStyle->isMutable());
     m_inlineStyle = other.m_inlineStyle;
 
     m_attributeVector.reserveCapacity(other.length());
@@ skipping 15 matching lines @@
 Attribute* UniqueElementData::getAttributeItem(const QualifiedName& name)
 {
     for (unsigned i = 0; i < length(); ++i) {
         if (m_attributeVector.at(i).name().matches(name))
             return &m_attributeVector.at(i);
     }
     return 0;
 }
 
 } // namespace WebCore