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

chrome/browser/extensions/api/tabs/tabs_windows_api.h

Index: chrome/browser/extensions/api/tabs/tabs_windows_api.h
diff --git a/chrome/browser/extensions/api/tabs/tabs_windows_api.h b/chrome/browser/extensions/api/tabs/tabs_windows_api.h
index 72a53a1bcbb09105af2f08fad05db809757e3fdc..4fe76e8ca72e7da6f34efd6bf2c22f1761835781 100644
--- a/chrome/browser/extensions/api/tabs/tabs_windows_api.h
+++ b/chrome/browser/extensions/api/tabs/tabs_windows_api.h
@@ -18,7 +18,7 @@ class TabsWindowsAPI : public BrowserContextKeyedAPI,
                        public EventRouter::Observer {
  public:
   explicit TabsWindowsAPI(content::BrowserContext* context);
-  virtual ~TabsWindowsAPI();
+  ~TabsWindowsAPI() override;
 
   // Convenience method to get the TabsWindowsAPI for a profile.
   static TabsWindowsAPI* Get(content::BrowserContext* context);
@@ -27,14 +27,13 @@ class TabsWindowsAPI : public BrowserContextKeyedAPI,
   WindowsEventRouter* windows_event_router();
 
   // KeyedService implementation.
-  virtual void Shutdown() override;
+  void Shutdown() override;
 
   // BrowserContextKeyedAPI implementation.
   static BrowserContextKeyedAPIFactory<TabsWindowsAPI>* GetFactoryInstance();
 
   // EventRouter::Observer implementation.
-  virtual void OnListenerAdded(const extensions::EventListenerInfo& details)
-      override;
+  void OnListenerAdded(const extensions::EventListenerInfo& details) override;
 
  private:
   friend class BrowserContextKeyedAPIFactory<TabsWindowsAPI>;