Virtual destructors should have virtual keyword.

chrome/browser/plugin_data_remover.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_PLUGIN_DATA_REMOVER_H_
 #define CHROME_BROWSER_PLUGIN_DATA_REMOVER_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "base/time.h"
@@ skipping 40 matching lines @@
   virtual void OnChannelOpened(const IPC::ChannelHandle& handle);
   virtual void OnError();
 
   // IPC::Channel::Listener methods.
   virtual bool OnMessageReceived(const IPC::Message& message);
   virtual void OnChannelError();
 
  private:
   friend class base::RefCountedThreadSafe<PluginDataRemover>;
   friend class PluginDataRemoverTest;
-  ~PluginDataRemover();
+  virtual ~PluginDataRemover();
 
   // Signals that we are finished with removing data (successful or not). This
   // method is safe to call multiple times.
   void SignalDone();
   // Connects the client side of a newly opened plug-in channel.
   void ConnectToChannel(const IPC::ChannelHandle& handle);
   // Handles the PluginHostMsg_ClearSiteDataResult message.
   void OnClearSiteDataResult(bool success);
   // Called when a timeout happens in order not to block the client
   // indefinitely.
   void OnTimeout();
 
   std::string mime_type_;
   bool is_removing_;
   // The point in time when we start removing data.
   base::Time remove_start_time_;
   // The point in time from which on we remove data.
   base::Time begin_time_;
   scoped_ptr<base::WaitableEvent> event_;
   // We own the channel, but it's used on the IO thread, so it needs to be
   // deleted there. It's NULL until we have opened a connection to the plug-in
   // process.
   IPC::Channel* channel_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginDataRemover);
 };
 
 #endif  // CHROME_BROWSER_PLUGIN_DATA_REMOVER_H_