replace NULL->nullptr in src/remoting.

remoting/host/desktop_environment.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_DESKTOP_ENVIRONMENT_H_
 #define REMOTING_HOST_DESKTOP_ENVIRONMENT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 48 matching lines @@
   // desktop environment.
   virtual scoped_ptr<GnubbyAuthHandler> CreateGnubbyAuthHandler(
       protocol::ClientStub* client_stub) = 0;
 };
 
 // Used to create |DesktopEnvironment| instances.
 class DesktopEnvironmentFactory {
  public:
   virtual ~DesktopEnvironmentFactory() {}
 
-  // Creates an instance of |DesktopEnvironment|. Returns a NULL pointer if
+  // Creates an instance of |DesktopEnvironment|. Returns a nullptr pointer if
   // the desktop environment could not be created for any reason (if the curtain
   // failed to active for instance). |client_session_control| must outlive
   // the created desktop environment.
   virtual scoped_ptr<DesktopEnvironment> Create(
       base::WeakPtr<ClientSessionControl> client_session_control) = 0;
 
   // Enables or disables the curtain mode.
   virtual void SetEnableCurtaining(bool enable) {}
 
   // Returns |true| if created |DesktopEnvironment| instances support audio
   // capture.
   virtual bool SupportsAudioCapture() const = 0;
 
   // Enables or disables gnubby authentication.
   virtual void SetEnableGnubbyAuth(bool enable) {}
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_DESKTOP_ENVIRONMENT_H_