Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/css/MediaQueryMatcher.cpp

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  *  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,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 83 matching lines @@
     if (!media)
         return false;
 
     OwnPtr<MediaQueryEvaluator> evaluator(prepareEvaluator());
     return evaluator && evaluator->eval(media);
 }
 
 PassRefPtr<MediaQueryList> MediaQueryMatcher::matchMedia(const String& query)
 {
     if (!m_document)
-        return 0;
+        return nullptr;
 
     RefPtr<MediaQuerySet> media = MediaQuerySet::create(query);
     // Add warning message to inspector whenever dpi/dpcm values are used for "screen" media.
     reportMediaQueryWarningIfNeeded(m_document, media.get());
     return MediaQueryList::create(this, media, evaluate(media.get()));
 }
 
 void MediaQueryMatcher::addListener(PassRefPtr<MediaQueryListListener> listener, PassRefPtr<MediaQueryList> query)
 {
     if (!m_document)
@@ skipping 32 matching lines @@
     ++m_evaluationRound;
     OwnPtr<MediaQueryEvaluator> evaluator = prepareEvaluator();
     if (!evaluator)
         return;
 
     for (size_t i = 0; i < m_listeners.size(); ++i)
         m_listeners[i]->evaluate(scriptState, evaluator.get());
 }
 
 }