GTTF: Add missing virtual destructors.

chrome/browser/signin/signin_tracker.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 CHROME_BROWSER_SIGNIN_SIGNIN_TRACKER_H_
 #define CHROME_BROWSER_SIGNIN_SIGNIN_TRACKER_H_
 
 #include "chrome/browser/api/sync/profile_sync_service_observer.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ skipping 43 matching lines @@
    public:
     // The GAIA credentials entered by the user have been validated.
     virtual void GaiaCredentialsValid() = 0;
 
     // The signin attempt failed. If this is called after GaiaCredentialsValid()
     // then it means there was an error launching one of the dependent services.
     virtual void SigninFailed(const GoogleServiceAuthError& error) = 0;
 
     // The signin attempt succeeded.
     virtual void SigninSuccess() = 0;
+
+   protected:
+    virtual ~Observer() { }
   };
 
   // The various states the login process can be in.
   enum LoginState {
     WAITING_FOR_GAIA_VALIDATION,
     SERVICES_INITIALIZING,
     SIGNIN_COMPLETE
   };
 
   // Creates a SigninTracker that tracks the signin status on the passed
@@ skipping 38 matching lines @@
   // Set to true when SigninManager has validated our credentials.
   bool credentials_valid_;
 
   // Used to listen to notifications from the SigninManager.
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninTracker);
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_SIGNIN_TRACKER_H_