Virtual destructors should have virtual keyword.

chrome/browser/background_application_list_model.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 CHROME_BROWSER_BACKGROUND_APPLICATION_LIST_MODEL_H_
 #define CHROME_BROWSER_BACKGROUND_APPLICATION_LIST_MODEL_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 27 matching lines @@
     // it no longer detects a previously known extension.
     virtual void OnApplicationListChanged();
 
    protected:
     virtual ~Observer();
   };
 
   // Create a new model associated with profile.
   explicit BackgroundApplicationListModel(Profile* profile);
 
-  ~BackgroundApplicationListModel();
+  virtual ~BackgroundApplicationListModel();
 
   // Associate observer with this model.
   void AddObserver(Observer* observer);
 
   // Return the icon associated with |extension| or NULL.  NULL indicates either
   // that there is no icon associated with the extension, or that a pending
   // task to retrieve the icon has not completed.  See the Observer class above.
   //
   // NOTE: The model manages the SkBitmap result, that is it "owns" the memory,
   //       releasing it if the associated background application is unloaded.
@@ skipping 69 matching lines @@
   ApplicationMap applications_;
   ExtensionList extensions_;
   ObserverList<Observer> observers_;
   Profile* profile_;
   NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundApplicationListModel);
 };
 
 #endif  // CHROME_BROWSER_BACKGROUND_APPLICATION_LIST_MODEL_H_