Virtual destructors should have virtual keyword.

content/renderer/audio_message_filter.h

 // Copyright (c) 2010 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.
 //
 // MessageFilter that handles audio messages and delegates them to audio
 // renderers. Created on render thread, AudioMessageFilter is operated on
 // IO thread (main thread of render process), it intercepts audio messages
 // and process them on IO thread since these messages are time critical.
 
 #ifndef CONTENT_RENDERER_AUDIO_MESSAGE_FILTER_H_
@@ skipping 35 matching lines @@
 
     // Called when notification of stream volume is received from the browser
     // process.
     virtual void OnVolume(double volume) = 0;
 
    protected:
     virtual ~Delegate() {}
   };
 
   explicit AudioMessageFilter(int32 route_id);
-  ~AudioMessageFilter();
+  virtual ~AudioMessageFilter();
 
   // Add a delegate to the map and return id of the entry.
   int32 AddDelegate(Delegate* delegate);
 
   // Remove a delegate referenced by |id| from the map.
   void RemoveDelegate(int32 id);
 
   // Sends an IPC message using |channel_|.
   bool Send(IPC::Message* message);
 
@@ skipping 44 matching lines @@
   IPC::Channel* channel_;
 
   int32 route_id_;
 
   MessageLoop* message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioMessageFilter);
 };
 
 #endif  // CONTENT_RENDERER_AUDIO_MESSAGE_FILTER_H_