Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/modules/mediastream/MediaStreamEvent.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 12 matching lines @@
  */
 
 #include "config.h"
 #include "modules/mediastream/MediaStreamEvent.h"
 
 #include "core/events/ThreadLocalEventNames.h"
 
 namespace WebCore {
 
 MediaStreamEventInit::MediaStreamEventInit()
-    : stream(0)
+    : stream(nullptr)
 {
 }
 
 PassRefPtr<MediaStreamEvent> MediaStreamEvent::create()
 {
     return adoptRef(new MediaStreamEvent);
 }
 
 PassRefPtr<MediaStreamEvent> MediaStreamEvent::create(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<MediaStream> stream)
 {
@@ skipping 39 matching lines @@
     return m_stream.get();
 }
 
 const AtomicString& MediaStreamEvent::interfaceName() const
 {
     return EventNames::MediaStreamEvent;
 }
 
 } // namespace WebCore