Replace NULL with nullptr or null in webrtc/base/.

webrtc/base/httpserver.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 33 matching lines @@
 
   int HandleConnection(StreamInterface* stream);
   // Due to sigslot issues, we can't destroy some streams at an arbitrary time.
   sigslot::signal3<HttpServer*, int, StreamInterface*> SignalConnectionClosed;
 
   // This signal occurs when the HTTP request headers have been received, but
   // before the request body is written to the request document.  By default,
   // the request document is a MemoryStream.  By handling this signal, the
   // document can be overridden, in which case the third signal argument should
   // be set to true.  In the case where the request body should be ignored,
-  // the document can be set to NULL.  Note that the transaction object is still
-  // owened by the HttpServer at this point.  
+  // the document can be set to null.  Note that the transaction object is still
+  // owened by the HttpServer at this point.
   sigslot::signal3<HttpServer*, HttpServerTransaction*, bool*>
     SignalHttpRequestHeader;
 
   // An HTTP request has been made, and is available in the transaction object.
   // Populate the transaction's response, and then return the object via the
   // Respond method.  Note that during this time, ownership of the transaction
   // object is transferred, so it may be passed between threads, although
   // respond must be called on the server's active thread.
   sigslot::signal2<HttpServer*, HttpServerTransaction*> SignalHttpRequest;
   void Respond(HttpServerTransaction* transaction);
@@ skipping 64 matching lines @@
                           StreamInterface* stream);
 
   std::unique_ptr<AsyncSocket> listener_;
 };
 
 //////////////////////////////////////////////////////////////////////
 
 }  // namespace rtc
 
 #endif // WEBRTC_BASE_HTTPSERVER_H__