Standardize usage of virtual/override/final in extensions/

extensions/browser/extension_message_filter.h

 // Copyright 2014 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 EXTENSIONS_BROWSER_EXTENSION_MESSAGE_FILTER_H_
 #define EXTENSIONS_BROWSER_EXTENSION_MESSAGE_FILTER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 25 matching lines @@
  public:
   ExtensionMessageFilter(int render_process_id,
                          content::BrowserContext* context);
 
   int render_process_id() { return render_process_id_; }
 
  private:
   friend class content::BrowserThread;
   friend class base::DeleteHelper<ExtensionMessageFilter>;
 
-  virtual ~ExtensionMessageFilter();
+  ~ExtensionMessageFilter() override;
 
   // content::BrowserMessageFilter implementation.
-  virtual void OverrideThreadForMessage(
-      const IPC::Message& message,
-      content::BrowserThread::ID* thread) override;
-  virtual void OnDestruct() const override;
-  virtual bool OnMessageReceived(const IPC::Message& message) override;
+  void OverrideThreadForMessage(const IPC::Message& message,
+                                content::BrowserThread::ID* thread) override;
+  void OnDestruct() const override;
+  bool OnMessageReceived(const IPC::Message& message) override;
 
   // Message handlers on the UI thread.
   void OnExtensionAddListener(const std::string& extension_id,
                               const GURL& listener_url,
                               const std::string& event_name);
   void OnExtensionRemoveListener(const std::string& extension_id,
                                  const GURL& listener_url,
                                  const std::string& event_name);
   void OnExtensionAddLazyListener(const std::string& extension_id,
                                   const std::string& event_name);
@@ skipping 43 matching lines @@
 
   // Weak pointers produced by this factory are bound to the IO thread.
   base::WeakPtrFactory<ExtensionMessageFilter> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionMessageFilter);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_MESSAGE_FILTER_H_