Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/platform/network/HTTPRequest.cpp

 /*
  * Copyright (C) 2011 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 16 matching lines @@
 #include "platform/network/HTTPRequest.h"
 
 #include "wtf/text/CString.h"
 
 namespace WebCore {
 
 PassRefPtr<HTTPRequest> HTTPRequest::parseHTTPRequestFromBuffer(const char* data, size_t length, String& failureReason)
 {
     if (!length) {
         failureReason = "No data to parse.";
-        return 0;
+        return nullptr;
     }
 
     // Request we will be building.
     RefPtr<HTTPRequest> request = HTTPRequest::create();
 
     // Advance a pointer through the data as needed.
     const char* pos = data;
     size_t remainingLength = length;
 
     // 1. Parse Method + URL.
     size_t requestLineLength = request->parseRequestLine(pos, remainingLength, failureReason);
     if (!requestLineLength)
-        return 0;
+        return nullptr;
     pos += requestLineLength;
     remainingLength -= requestLineLength;
 
     // 2. Parse HTTP Headers.
     size_t headersLength = request->parseHeaders(pos, remainingLength, failureReason);
     if (!headersLength)
-        return 0;
+        return nullptr;
     pos += headersLength;
     remainingLength -= headersLength;
 
     // 3. Parse HTTP Data.
     size_t dataLength = request->parseRequestBody(pos, remainingLength);
     remainingLength -= dataLength;
 
     // We should have processed the entire input.
     ASSERT(!remainingLength);
     return request.release();
@@ skipping 40 matching lines @@
     , m_httpVersion(version)
     , m_requestMethod(requestMethod)
 {
 }
 
 HTTPRequest::~HTTPRequest()
 {
 }
 
 } // namespace WebCore