Standardize usage of virtual/override/final in extensions/

extensions/renderer/script_injection_manager.h

Index: extensions/renderer/script_injection_manager.h
diff --git a/extensions/renderer/script_injection_manager.h b/extensions/renderer/script_injection_manager.h
index f3f3e52b0325ebad608ecdf094176af34261b9c5..537a3e1aa26469e56e0bda7662dec021effd666a 100644
--- a/extensions/renderer/script_injection_manager.h
+++ b/extensions/renderer/script_injection_manager.h
@@ -54,9 +54,8 @@ class ScriptInjectionManager : public UserScriptSetManager::Observer {
   typedef std::map<blink::WebFrame*, UserScript::RunLocation> FrameStatusMap;
 
   // UserScriptSetManager::Observer implementation.
-  virtual void OnUserScriptsUpdated(
-      const std::set<std::string>& changed_extensions,
-      const std::vector<UserScript*>& scripts) override;
+  void OnUserScriptsUpdated(const std::set<std::string>& changed_extensions,
+                            const std::vector<UserScript*>& scripts) override;
 
   // Notifies that an RVOHelper should be removed.
   void RemoveObserver(RVOHelper* helper);