Standardize usage of virtual/override/final in apps/

apps/app_load_service.h

Index: apps/app_load_service.h
diff --git a/apps/app_load_service.h b/apps/app_load_service.h
index 566672ecbfef4d29944b05ec399008c60c0bfbb0..aa9cc984078fc2ac0138b65b2a1a44d7de4e4d55 100644
--- a/apps/app_load_service.h
+++ b/apps/app_load_service.h
@@ -44,7 +44,7 @@ class AppLoadService : public KeyedService,
   };
 
   explicit AppLoadService(Profile* profile);
-  virtual ~AppLoadService();
+  ~AppLoadService() override;
 
   // Reload the application with the given id and then send it the OnRestarted
   // event.
@@ -65,12 +65,12 @@ class AppLoadService : public KeyedService,
 
  private:
   // content::NotificationObserver.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) override;
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
 
   // extensions::ExtensionRegistryObserver.
-  virtual void OnExtensionUnloaded(
+  void OnExtensionUnloaded(
       content::BrowserContext* browser_context,
       const extensions::Extension* extension,
       extensions::UnloadedExtensionInfo::Reason reason) override;