Clean up remoting project

remoting/host/user_authenticator.h

 // Copyright (c) 2011 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_USER_AUTHENTICATOR_H_
 #define REMOTING_HOST_USER_AUTHENTICATOR_H_
 
 #include <string>
 
+#include "base/memory/ref_counted.h"
+
 namespace remoting {
 
 // Interface for authenticating users for access to remote desktop session.
 // Implementation is platform-specific.
 // Implementations may assume each instance of this class handles only a
 // single Authenticate request.
 
 // TODO(lambroslambrou): Decide whether this needs an asychronous interface
 // (for example AuthenticateStart()..AuthenticateEndCallback()), or whether the
 // multi-threading policy could be handled by the caller.
-class UserAuthenticator {
+class UserAuthenticator : public base::RefCountedThreadSafe<UserAuthenticator> {
  public:
   virtual ~UserAuthenticator() {}
 
   // Create platform-specific authenticator.
   static UserAuthenticator* Create();
 
   // Authenticate a user, returning true if the username/password are valid.
   virtual bool Authenticate(const std::string& username,
                             const std::string& password) = 0;
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_USER_AUTHENTICATOR_H_