Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/html/canvas/WebGLVertexArrayObjectOES.cpp

 /*
  * Copyright (C) 2011 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 22 matching lines @@
 
 PassRefPtr<WebGLVertexArrayObjectOES> WebGLVertexArrayObjectOES::create(WebGLRenderingContext* ctx, VaoType type)
 {
     return adoptRef(new WebGLVertexArrayObjectOES(ctx, type));
 }
 
 WebGLVertexArrayObjectOES::WebGLVertexArrayObjectOES(WebGLRenderingContext* ctx, VaoType type)
     : WebGLContextObject(ctx)
     , m_type(type)
     , m_hasEverBeenBound(false)
-    , m_boundElementArrayBuffer(0)
+    , m_boundElementArrayBuffer(nullptr)
 {
     ScriptWrappable::init(this);
     m_vertexAttribState.resize(ctx->maxVertexAttribs());
 
     switch (m_type) {
     case VaoTypeDefault:
         break;
     default:
         setObject(context()->webGraphicsContext3D()->createVertexArrayOES());
         break;
@@ skipping 54 matching lines @@
     state.normalized = normalized;
     state.stride = validatedStride;
     state.originalStride = stride;
     state.offset = offset;
 }
 
 void WebGLVertexArrayObjectOES::unbindBuffer(PassRefPtr<WebGLBuffer> buffer)
 {
     if (m_boundElementArrayBuffer == buffer) {
         m_boundElementArrayBuffer->onDetached(context()->webGraphicsContext3D());
-        m_boundElementArrayBuffer = 0;
+        m_boundElementArrayBuffer = nullptr;
     }
 
     for (size_t i = 0; i < m_vertexAttribState.size(); ++i) {
         VertexAttribState& state = m_vertexAttribState[i];
         if (state.bufferBinding == buffer) {
             buffer->onDetached(context()->webGraphicsContext3D());
-            state.bufferBinding = 0;
+            state.bufferBinding = nullptr;
         }
     }
 }
 
 void WebGLVertexArrayObjectOES::setVertexAttribDivisor(GLuint index, GLuint divisor)
 {
     VertexAttribState& state = m_vertexAttribState[index];
     state.divisor = divisor;
 }
 
 }