Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/css/CSSMatrix.cpp

 /*
  * Copyright (C) 2008 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 76 matching lines @@
         m_matrix = t;
     } else { // There is something there but parsing failed.
         exceptionState.throwDOMException(SyntaxError, "Failed to parse '" + string + "'.");
     }
 }
 
 // Perform a concatenation of the matrices (this * secondMatrix)
 PassRefPtrWillBeRawPtr<CSSMatrix> CSSMatrix::multiply(CSSMatrix* secondMatrix) const
 {
     if (!secondMatrix)
-        return 0;
+        return nullptr;
 
     return CSSMatrix::create(TransformationMatrix(m_matrix).multiply(secondMatrix->m_matrix));
 }
 
 PassRefPtrWillBeRawPtr<CSSMatrix> CSSMatrix::inverse(ExceptionState& exceptionState) const
 {
     if (!m_matrix.isInvertible()) {
         exceptionState.throwDOMException(NotSupportedError, "The matrix is not invertable.");
-        return 0;
+        return nullptr;
     }
 
     return CSSMatrix::create(m_matrix.inverse());
 }
 
 PassRefPtrWillBeRawPtr<CSSMatrix> CSSMatrix::translate(double x, double y, double z) const
 {
     if (std::isnan(x))
         x = 0;
     if (std::isnan(y))
@@ skipping 67 matching lines @@
     if (m_matrix.isAffine())
         return String::format("matrix(%f, %f, %f, %f, %f, %f)", m_matrix.a(), m_matrix.b(), m_matrix.c(), m_matrix.d(), m_matrix.e(), m_matrix.f());
     return String::format("matrix3d(%f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f)",
     m_matrix.m11(), m_matrix.m12(), m_matrix.m13(), m_matrix.m14(),
     m_matrix.m21(), m_matrix.m22(), m_matrix.m23(), m_matrix.m24(),
     m_matrix.m31(), m_matrix.m32(), m_matrix.m33(), m_matrix.m34(),
     m_matrix.m41(), m_matrix.m42(), m_matrix.m43(), m_matrix.m44());
 }
 
 } // namespace WebCore