Virtual destructors should have virtual keyword.

content/browser/mime_registry_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.
 
 #ifndef CONTENT_BROWSER_MIME_REGISTRY_MESSAGE_FILTER_H_
 #define CONTENT_BROWSER_MIME_REGISTRY_MESSAGE_FILTER_H_
 
 #include "base/file_path.h"
 #include "content/browser/browser_message_filter.h"
 
 class MimeRegistryMessageFilter : public BrowserMessageFilter {
  public:
   MimeRegistryMessageFilter();
 
   virtual void OverrideThreadForMessage(const IPC::Message& message,
                                         BrowserThread::ID* thread);
   virtual bool OnMessageReceived(const IPC::Message& message,
                                  bool* message_was_ok);
 
  private:
-  ~MimeRegistryMessageFilter();
+  virtual ~MimeRegistryMessageFilter();
 
   void OnGetMimeTypeFromExtension(const FilePath::StringType& ext,
                                   std::string* mime_type);
   void OnGetMimeTypeFromFile(const FilePath& file_path,
                              std::string* mime_type);
   void OnGetPreferredExtensionForMimeType(const std::string& mime_type,
                                           FilePath::StringType* extension);
 };
 
 #endif  // CONTENT_BROWSER_MIME_REGISTRY_MESSAGE_FILTER_H_