GTTF: Add missing virtual destructors.

chrome/browser/extensions/event_router.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_EVENT_ROUTER_H_
 #define CHROME_BROWSER_EXTENSIONS_EVENT_ROUTER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 35 matching lines @@
   enum UserGestureState {
     USER_GESTURE_UNKNOWN = 0,
     USER_GESTURE_ENABLED = 1,
     USER_GESTURE_NOT_ENABLED = 2,
   };
 
   // Observers register interest in events with a particular name and are
   // notified when a listener is added or removed for that |event_name|.
   class Observer {
    public:
+    virtual ~Observer() {}
+
     // Called when a listener is added.
     virtual void OnListenerAdded(const EventListenerInfo& details) {}
     // Called when a listener is removed.
     virtual void OnListenerRemoved(const EventListenerInfo& details) {}
   };
 
   // Sends an event via ipc_sender to the given extension. Can be called on any
   // thread.
   static void DispatchEvent(IPC::Sender* ipc_sender,
                             const std::string& extension_id,
@@ skipping 224 matching lines @@
   EventListenerInfo(const std::string& event_name,
                     const std::string& extension_id);
 
   const std::string event_name;
   const std::string extension_id;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EVENT_ROUTER_H_