Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/modules/webaudio/OfflineAudioContext.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:
  * 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 25 matching lines @@
 
 namespace WebCore {
 
 PassRefPtr<OfflineAudioContext> OfflineAudioContext::create(ExecutionContext* context, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate, ExceptionState& exceptionState)
 {
     // FIXME: add support for workers.
     if (!context || !context->isDocument()) {
         exceptionState.throwDOMException(
             NotSupportedError,
             "Workers are not supported.");
-        return 0;
+        return nullptr;
     }
 
     Document* document = toDocument(context);
 
     if (!numberOfFrames) {
         exceptionState.throwDOMException(SyntaxError, "number of frames cannot be zero.");
-        return 0;
+        return nullptr;
     }
 
     if (numberOfChannels > 10) {
         exceptionState.throwDOMException(SyntaxError, "number of channels (" + String::number(numberOfChannels) + ") exceeds maximum (10).");
-        return 0;
+        return nullptr;
     }
 
     if (!isSampleRateRangeGood(sampleRate)) {
         exceptionState.throwDOMException(SyntaxError, "sample rate (" + String::number(sampleRate) + ") must be in the range 44100-96000 Hz.");
-        return 0;
+        return nullptr;
     }
 
     RefPtr<OfflineAudioContext> audioContext(adoptRef(new OfflineAudioContext(document, numberOfChannels, numberOfFrames, sampleRate)));
     audioContext->suspendIfNeeded();
     return audioContext.release();
 }
 
 OfflineAudioContext::OfflineAudioContext(Document* document, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate)
     : AudioContext(document, numberOfChannels, numberOfFrames, sampleRate)
 {
     ScriptWrappable::init(this);
 }
 
 OfflineAudioContext::~OfflineAudioContext()
 {
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)