GTTF: Add missing virtual destructors.

chrome/browser/signin/about_signin_internals.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_ABOUT_SIGNIN_INTERNALS_H_
 #define CHROME_BROWSER_SIGNIN_ABOUT_SIGNIN_INTERNALS_H_
 
 #include <map>
 #include <string>
 
@@ skipping 12 matching lines @@
 // to propagate to about:signin-internals via SigninInternalsUI.
 class AboutSigninInternals
     : public ProfileKeyedService,
       public signin_internals_util::SigninDiagnosticsObserver {
  public:
   class Observer {
    public:
     // |info| will contain the dictionary of signin_status_ values as indicated
     // in the comments for GetSigninStatus() below.
     virtual void OnSigninStateChanged(scoped_ptr<DictionaryValue> info) = 0;
+
+   protected:
+    virtual ~Observer() { }
   };
 
   AboutSigninInternals();
   virtual ~AboutSigninInternals();
 
   // Each instance of SigninInternalsUI adds itself as an observer to be
   // notified of all updates that AboutSigninInternals receives.
   void AddSigninObserver(Observer* observer);
   void RemoveSigninObserver(Observer* observer);
 
@@ skipping 48 matching lines @@
   // Encapsulates the actual signin and token related values.
   // Most of the values are mirrored in the prefs for persistance.
   signin_internals_util::SigninStatus signin_status_;
 
   ObserverList<Observer> signin_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(AboutSigninInternals);
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_ABOUT_SIGNIN_INTERNALS_H_