Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/frame/History.cpp

 /*
  * Copyright (C) 2007 Apple 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 26 matching lines @@
 #include "core/page/BackForwardClient.h"
 #include "core/page/Page.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/SecurityOrigin.h"
 #include "wtf/MainThread.h"
 
 namespace WebCore {
 
 History::History(Frame* frame)
     : DOMWindowProperty(frame)
-    , m_lastStateObjectRequested(0)
+    , m_lastStateObjectRequested(nullptr)
 {
     ScriptWrappable::init(this);
 }
 
 unsigned History::length() const
 {
     if (!m_frame)
         return 0;
     if (!m_frame->page())
         return 0;
@@ skipping 73 matching lines @@
     KURL fullURL = urlForState(urlString);
     if (!fullURL.isValid() || !m_frame->document()->securityOrigin()->canRequest(fullURL)) {
         // We can safely expose the URL to JavaScript, as a) no redirection takes place: JavaScript already had this URL, b) JavaScript can only access a same-origin History object.
         exceptionState.throwSecurityError("A history state object with URL '" + fullURL.elidedString() + "' cannot be created in a document with origin '" + m_frame->document()->securityOrigin()->toString() + "'.");
         return;
     }
     m_frame->loader().updateForSameDocumentNavigation(fullURL, SameDocumentNavigationHistoryApi, data, updateBackForwardListPolicy);
 }
 
 } // namespace WebCore