Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/dom/ScriptedAnimationController.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 92 matching lines @@
     Vector<RefPtr<Event> > events;
     events.swap(m_eventQueue);
     m_perFrameEvents.clear();
 
     for (size_t i = 0; i < events.size(); ++i) {
         EventTarget* eventTarget = events[i]->target();
         // FIXME: we should figure out how to make dispatchEvent properly virtual to avoid
         // special casting window.
         // FIXME: We should not fire events for nodes that are no longer in the tree.
         if (DOMWindow* window = eventTarget->toDOMWindow())
-            window->dispatchEvent(events[i], 0);
+            window->dispatchEvent(events[i], nullptr);
         else
             eventTarget->dispatchEvent(events[i]);
     }
 }
 
 void ScriptedAnimationController::executeCallbacks(double monotonicTimeNow)
 {
     // dispatchEvents() runs script which can cause the document to be destroyed.
     if (!m_document)
         return;
@@ skipping 59 matching lines @@
         return;
 
     if (!m_callbacks.size() && !m_eventQueue.size())
         return;
 
     if (FrameView* frameView = m_document->view())
         frameView->scheduleAnimation();
 }
 
 }