Standardize usage of virtual/override/final in content/

content/child/npapi/plugin_string_stream.h

 // Copyright (c) 2006-2008 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_CHILD_PLUGIN_STRING_STREAM_H_
 #define CONTENT_CHILD_PLUGIN_STRING_STREAM_H_
 
 #include "content/child/npapi/plugin_stream.h"
 
 class GURL;
@@ skipping 11 matching lines @@
   PluginStringStream(PluginInstance* instance,
                      const GURL& url,
                      bool notify_needed,
                      void* notify_data);
 
   // Initiates the sending of data to the plugin.
   void SendToPlugin(const std::string& data,
                     const std::string& mime_type);
 
  private:
-  virtual ~PluginStringStream();
+  ~PluginStringStream() override;
 
   DISALLOW_COPY_AND_ASSIGN(PluginStringStream);
 };
 
 
 }  // namespace content
 
 #endif // CONTENT_CHILD_PLUGIN_STRING_STREAM_H_