Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/css/CSSFontSelector.cpp

 /*
  * Copyright (C) 2007, 2008, 2011 Apple Inc. All rights reserved.
  *           (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * 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 170 matching lines @@
 }
 
 PassRefPtr<FontData> CSSFontSelector::getFontData(const FontDescription& fontDescription, const AtomicString& familyName)
 {
     if (CSSSegmentedFontFace* face = m_fontFaceCache.get(fontDescription, familyName))
         return face->getFontData(fontDescription);
 
     // Try to return the correct font based off our settings, in case we were handed the generic font family name.
     AtomicString settingsFamilyName = familyNameFromSettings(m_genericFontFamilySettings, fontDescription, familyName);
     if (settingsFamilyName.isEmpty())
-        return 0;
+        return nullptr;
 
     return FontCache::fontCache()->getFontData(fontDescription, settingsFamilyName);
 }
 
 void CSSFontSelector::willUseFontData(const FontDescription& fontDescription, const AtomicString& family)
 {
     CSSSegmentedFontFace* face = m_fontFaceCache.get(fontDescription, family);
     if (face)
         face->willUseFontData(fontDescription);
 }
@@ skipping 14 matching lines @@
     m_fontLoader.loadPendingFonts();
 }
 
 void CSSFontSelector::updateGenericFontFamilySettings(Document& document)
 {
     ASSERT(document.settings());
     m_genericFontFamilySettings = document.settings()->genericFontFamilySettings();
 }
 
 }