Standardize usage of virtual/override/final in extensions/

extensions/renderer/utils_native_handler.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_RENDERER_UTILS_NATIVE_HANDLER_H_
 #define EXTENSIONS_RENDERER_UTILS_NATIVE_HANDLER_H_
 
 #include "extensions/renderer/object_backed_native_handler.h"
 
 namespace extensions {
 class ScriptContext;
 
 class UtilsNativeHandler : public ObjectBackedNativeHandler {
  public:
   explicit UtilsNativeHandler(ScriptContext* context);
-  virtual ~UtilsNativeHandler();
+  ~UtilsNativeHandler() override;
 
  private:
   // |args| consists of two arguments: a public class name, and a reference
   // to the implementation class. CreateClassWrapper returns a new class
   // that wraps the implementation, while hiding its members.
   void CreateClassWrapper(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   // |args| consists of one argument: an arbitrary value. Returns a deep copy of
   // that value. The copy will have no references to nested values of the
   // argument.
   void DeepCopy(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   DISALLOW_COPY_AND_ASSIGN(UtilsNativeHandler);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_UTILS_NATIVE_HANDLER_H_