replace NULL->nullptr in src/remoting.

remoting/host/client_session.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_HOST_CLIENT_SESSION_H_
 #define REMOTING_HOST_CLIENT_SESSION_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 201 matching lines @@
   base::OneShotTimer<ClientSession> max_duration_timer_;
 
   scoped_refptr<base::SingleThreadTaskRunner> audio_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> input_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> video_capture_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> video_encode_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> network_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
 
   // Schedulers for audio and video capture.
-  // |video_scheduler_| may be NULL if the video channel is not required - see
-  // ResetVideoPipeline().
+  // |video_scheduler_| may be nullptr if the video channel is not required -
+  // see ResetVideoPipeline().
   scoped_refptr<AudioScheduler> audio_scheduler_;
   scoped_refptr<VideoScheduler> video_scheduler_;
 
   // The set of all capabilities supported by the client.
   scoped_ptr<std::string> client_capabilities_;
 
   // The set of all capabilities supported by the host.
   std::string host_capabilities_;
 
   // The set of all capabilities negotiated between client and host.
@@ skipping 22 matching lines @@
   // Used to disable callbacks to |this| once DisconnectSession() has been
   // called.
   base::WeakPtrFactory<ClientSessionControl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ClientSession);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_CLIENT_SESSION_H_