Standardize usage of virtual/override/final in chrome/browser/ui/

chrome/browser/ui/webui/interstitials/interstitial_ui.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 CHROME_BROWSER_UI_WEBUI_INTERSTITIALS_INTERSTITIAL_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_INTERSTITIALS_INTERSTITIAL_UI_H_
 
 #include <string>
 
 #include "content/public/browser/url_data_source.h"
 #include "content/public/browser/web_ui_controller.h"
 
 class Profile;
 
 namespace content {
 class WebContents;
 }
 
 class InterstitialUI : public content::WebUIController {
  public:
   explicit InterstitialUI(content::WebUI* web_ui);
 
-  virtual ~InterstitialUI();
+  ~InterstitialUI() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(InterstitialUI);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_INTERSTITIALS_INTERSTITIAL_UI_H_