Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/svg/SVGFESpecularLightingElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2005 Oliver Hunt <oliver@nerget.com>
  *
  * 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.
  *
@@ skipping 166 matching lines @@
 
     // The light element has different attribute names so attrName can identify the requested attribute.
     primitiveAttributeChanged(attrName);
 }
 
 PassRefPtr<FilterEffect> SVGFESpecularLightingElement::build(SVGFilterBuilder* filterBuilder, Filter* filter)
 {
     FilterEffect* input1 = filterBuilder->getEffectById(AtomicString(m_in1->currentValue()->value()));
 
     if (!input1)
-        return 0;
+        return nullptr;
 
     RefPtr<LightSource> lightSource = SVGFELightElement::findLightSource(this);
     if (!lightSource)
-        return 0;
+        return nullptr;
 
     RenderObject* renderer = this->renderer();
     if (!renderer)
-        return 0;
+        return nullptr;
 
     ASSERT(renderer->style());
     Color color = renderer->style()->svgStyle()->lightingColor();
 
     RefPtr<FilterEffect> effect = FESpecularLighting::create(filter, color, m_surfaceScale->currentValue()->value(), m_specularConstant->currentValue()->value(),
         m_specularExponent->currentValue()->value(), kernelUnitLengthX()->currentValue()->value(), kernelUnitLengthY()->currentValue()->value(), lightSource.release());
     effect->inputEffects().append(input1);
     return effect.release();
 }
 
 }