GTTF: Add missing virtual destructors.

chrome/browser/extensions/extension_warning_service.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_EXTENSIONS_EXTENSION_WARNING_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_WARNING_SERVICE_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 19 matching lines @@
 // Manages a set of warnings caused by extensions. These warnings (e.g.
 // conflicting modifications of network requests by extensions, slow extensions,
 // etc.) trigger a warning badge in the UI and and provide means to resolve
 // them. This class must be used on the UI thread only.
 class ExtensionWarningService : public content::NotificationObserver,
                                 public base::NonThreadSafe {
  public:
   class Observer {
    public:
     virtual void ExtensionWarningsChanged() = 0;
+
+   protected:
+    virtual ~Observer() { }
   };
 
   // |profile| may be NULL for testing. In this case, be sure to not insert
   // any warnings.
   explicit ExtensionWarningService(Profile* profile);
   virtual ~ExtensionWarningService();
 
   // Clears all warnings of types contained in |types| and notifies observers
   // of the changed warnings.
   void ClearWarnings(const std::set<ExtensionWarning::WarningType>& types);
@@ skipping 33 matching lines @@
   content::NotificationRegistrar registrar_;
 
   Profile* profile_;
 
   ObserverList<Observer> observer_list_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_WARNING_SERVICE_H_