Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/platform/exported/WebHTTPBody.cpp

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 125 matching lines @@
 {
     // Currently we only support filesystem URL.
     ASSERT(KURL(url).protocolIs("filesystem"));
     ensureMutable();
     m_private->appendFileSystemURLRange(url, start, length, modificationTime);
 }
 
 void WebHTTPBody::appendBlob(const WebString& uuid)
 {
     ensureMutable();
-    m_private->appendBlob(uuid, 0);
+    m_private->appendBlob(uuid, nullptr);
 }
 
 long long WebHTTPBody::identifier() const
 {
     ASSERT(!isNull());
     return m_private->identifier();
 }
 
 void WebHTTPBody::setIdentifier(long long identifier)
 {
@@ skipping 36 matching lines @@
 }
 
 void WebHTTPBody::ensureMutable()
 {
     ASSERT(!isNull());
     if (!m_private->hasOneRef())
         assign(static_cast<WebHTTPBodyPrivate*>(m_private->copy().leakRef()));
 }
 
 } // namespace blink