Clean up remoting project

remoting/host/user_authenticator.h

Index: remoting/host/user_authenticator.h
diff --git a/remoting/host/user_authenticator.h b/remoting/host/user_authenticator.h
index b6f6a7ff906f53079111acc85eec5f9c08e7da88..e4c2c6ffa4d9e86b9e6a1b679819a48930487e95 100644
--- a/remoting/host/user_authenticator.h
+++ b/remoting/host/user_authenticator.h
@@ -7,6 +7,8 @@
 
 #include <string>
 
+#include "base/memory/ref_counted.h"
+
 namespace remoting {
 
 // Interface for authenticating users for access to remote desktop session.
@@ -17,7 +19,7 @@ namespace remoting {
 // 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() {}