Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/css/CSSParserValues.cpp

 /*
  * Copyright (C) 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 140 matching lines @@
     case CSSPrimitiveValue::CSS_UNICODE_RANGE:
     case CSSPrimitiveValue::CSS_PARSER_OPERATOR:
     case CSSPrimitiveValue::CSS_PARSER_INTEGER:
     case CSSPrimitiveValue::CSS_PARSER_IDENTIFIER:
     case CSSPrimitiveValue::CSS_COUNTER_NAME:
     case CSSPrimitiveValue::CSS_SHAPE:
     case CSSPrimitiveValue::CSS_QUAD:
     case CSSPrimitiveValue::CSS_CALC:
     case CSSPrimitiveValue::CSS_CALC_PERCENTAGE_WITH_NUMBER:
     case CSSPrimitiveValue::CSS_CALC_PERCENTAGE_WITH_LENGTH:
-        return 0;
+        return nullptr;
     }
 
     ASSERT_NOT_REACHED();
-    return 0;
+    return nullptr;
 }
 
 CSSParserSelector::CSSParserSelector()
     : m_selector(adoptPtr(new CSSSelector()))
     , m_functionArgumentSelector(0)
 {
 }
 
 CSSParserSelector::CSSParserSelector(const QualifiedName& tagQName)
     : m_selector(adoptPtr(new CSSSelector(tagQName)))
@@ skipping 76 matching lines @@
 {
     CSSParserSelector* selector = const_cast<CSSParserSelector*>(this);
     do {
         if (selector->isDistributedPseudoElement())
             return selector;
     } while ((selector = selector->tagHistory()));
     return 0;
 }
 
 } // namespace WebCore