Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/modules/mediasource/WebKitSourceBuffer.cpp

 /*
  * Copyright (C) 2012 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 61 matching lines @@
 WebKitSourceBuffer::~WebKitSourceBuffer()
 {
 }
 
 PassRefPtr<TimeRanges> WebKitSourceBuffer::buffered(ExceptionState& exceptionState) const
 {
     // Section 3.1 buffered attribute steps.
     // 1. If this object has been removed from the sourceBuffers attribute of the parent media source then throw an
     //    InvalidStateError exception and abort these steps.
     if (throwExceptionIfRemoved(isRemoved(), exceptionState))
-        return 0;
+        return nullptr;
 
     // 2. Return a new static normalized TimeRanges object for the media segments buffered.
     return TimeRanges::create(m_webSourceBuffer->buffered());
 }
 
 double WebKitSourceBuffer::timestampOffset() const
 {
     return m_timestampOffset;
 }
 
@@ skipping 79 matching lines @@
 {
     return !m_source;
 }
 
 void WebKitSourceBuffer::trace(Visitor* visitor)
 {
     visitor->trace(m_source);
 }
 
 } // namespace WebCore