Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/svg/SVGElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
  *
  * 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
@@ skipping 266 matching lines @@
     if (titleElement)
         return titleElement->innerText();
 
     // Otherwise return a null/empty string.
     return String();
 }
 
 PassRefPtrWillBeRawPtr<CSSValue> SVGElement::getPresentationAttribute(const AtomicString& name)
 {
     if (!hasAttributesWithoutUpdate())
-        return 0;
+        return nullptr;
 
     QualifiedName attributeName(nullAtom, name, nullAtom);
     const Attribute* attr = getAttributeItem(attributeName);
     if (!attr)
-        return 0;
+        return nullptr;
 
     RefPtr<MutableStylePropertySet> style = MutableStylePropertySet::create(SVGAttributeMode);
     CSSPropertyID propertyID = SVGElement::cssPropertyIdForSVGAttributeName(attr->name());
     style->setProperty(propertyID, attr->value());
     RefPtrWillBeRawPtr<CSSValue> cssValue = style->getPropertyCSSValue(propertyID);
-    return cssValue ? cssValue->cloneForCSSOM() : 0;
+    return cssValue ? cssValue->cloneForCSSOM() : nullptr;
 }
 
 
 bool SVGElement::instanceUpdatesBlocked() const
 {
     return hasSVGRareData() && svgRareData()->instanceUpdatesBlocked();
 }
 
 void SVGElement::setInstanceUpdatesBlocked(bool value)
 {
@@ skipping 882 matching lines @@
         animatableAttributes.add(SVGNames::zAttr);
     }
 
     if (name == classAttr)
         return true;
 
     return animatableAttributes.contains(name);
 }
 #endif
 }