Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/css/FontFaceCache.cpp

 /*
  * Copyright (C) 2007, 2008, 2011 Apple Inc. All rights reserved.
  * 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 44 matching lines @@
 }
 
 void FontFaceCache::addFontFace(CSSFontSelector* cssFontSelector, PassRefPtr<FontFace> prpFontFace, bool cssConnected)
 {
     RefPtr<FontFace> fontFace = prpFontFace;
 
     OwnPtr<TraitsMap>& familyFontFaces = m_fontFaces.add(fontFace->family(), nullptr).storedValue->value;
     if (!familyFontFaces)
         familyFontFaces = adoptPtr(new TraitsMap);
 
-    RefPtr<CSSSegmentedFontFace>& segmentedFontFace = familyFontFaces->add(fontFace->traitsMask(), 0).storedValue->value;
+    RefPtr<CSSSegmentedFontFace>& segmentedFontFace = familyFontFaces->add(fontFace->traitsMask(), nullptr).storedValue->value;
     if (!segmentedFontFace)
         segmentedFontFace = CSSSegmentedFontFace::create(cssFontSelector, static_cast<FontTraitsMask>(fontFace->traitsMask()));
 
     segmentedFontFace->addFontFace(fontFace, cssConnected);
     if (cssConnected)
         m_cssConnectedFontFaces.add(fontFace);
 
     ++m_version;
 }
 
@@ skipping 123 matching lines @@
     TraitsMap* familyFontFaces = m_fontFaces.get(family);
     if (!familyFontFaces || familyFontFaces->isEmpty())
         return 0;
 
     OwnPtr<TraitsMap>& segmentedFontFaceCache = m_fonts.add(family, nullptr).storedValue->value;
     if (!segmentedFontFaceCache)
         segmentedFontFaceCache = adoptPtr(new TraitsMap);
 
     FontTraitsMask traitsMask = fontDescription.traitsMask();
 
-    RefPtr<CSSSegmentedFontFace>& face = segmentedFontFaceCache->add(traitsMask, 0).storedValue->value;
+    RefPtr<CSSSegmentedFontFace>& face = segmentedFontFaceCache->add(traitsMask, nullptr).storedValue->value;
     if (!face) {
         for (TraitsMap::const_iterator i = familyFontFaces->begin(); i != familyFontFaces->end(); ++i) {
             CSSSegmentedFontFace* candidate = i->value.get();
             unsigned candidateTraitsMask = candidate->traitsMask();
             if ((traitsMask & FontStyleNormalMask) && !(candidateTraitsMask & FontStyleNormalMask))
                 continue;
             if ((traitsMask & FontVariantNormalMask) && !(candidateTraitsMask & FontVariantNormalMask))
                 continue;
             if (!face || compareFontFaces(candidate, face.get(), traitsMask))
                 face = candidate;
         }
     }
     return face.get();
 }
 
 }