Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/events/DOMWindowEventQueue.cpp

 /*
  * Copyright (C) 2010 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 84 matching lines @@
     m_pendingEventTimer->stop();
     m_queuedEvents.clear();
 }
 
 void DOMWindowEventQueue::pendingEventTimerFired()
 {
     ASSERT(!m_pendingEventTimer->isActive());
     ASSERT(!m_queuedEvents.isEmpty());
 
     // Insert a marker for where we should stop.
-    ASSERT(!m_queuedEvents.contains(0));
-    bool wasAdded = m_queuedEvents.add(0).isNewEntry;
+    ASSERT(!m_queuedEvents.contains(nullptr));
+    bool wasAdded = m_queuedEvents.add(nullptr).isNewEntry;
     ASSERT_UNUSED(wasAdded, wasAdded); // It should not have already been in the list.
 
     RefPtr<DOMWindowEventQueue> protector(this);
 
     while (!m_queuedEvents.isEmpty()) {
         ListHashSet<RefPtr<Event>, 16>::iterator iter = m_queuedEvents.begin();
         RefPtr<Event> event = *iter;
         m_queuedEvents.remove(iter);
         if (!event)
             break;
         dispatchEvent(event.get());
     }
 }
 
 void DOMWindowEventQueue::dispatchEvent(PassRefPtr<Event> event)
 {
     EventTarget* eventTarget = event->target();
     if (eventTarget->toDOMWindow())
-        eventTarget->toDOMWindow()->dispatchEvent(event, 0);
+        eventTarget->toDOMWindow()->dispatchEvent(event, nullptr);
     else
         eventTarget->dispatchEvent(event);
 }
 
 }