Standardize usage of virtual/override/final in ui/

ui/app_list/search/history.h

Index: ui/app_list/search/history.h
diff --git a/ui/app_list/search/history.h b/ui/app_list/search/history.h
index 2a87813b3f265968beefc491a6c6232add69a5a6..4026ec10616324be3035872fc5f725ee187be1fc 100644
--- a/ui/app_list/search/history.h
+++ b/ui/app_list/search/history.h
@@ -35,7 +35,7 @@ class APP_LIST_EXPORT History : public KeyedService,
                                 public HistoryDataObserver {
  public:
   explicit History(scoped_refptr<HistoryDataStore> store);
-  virtual ~History();
+  ~History() override;
 
   // Returns true if the service is ready.
   bool IsReady() const;
@@ -51,7 +51,7 @@ class APP_LIST_EXPORT History : public KeyedService,
   friend class app_list::test::SearchHistoryTest;
 
   // HistoryDataObserver overrides:
-  virtual void OnHistoryDataLoadedFromStore() override;
+  void OnHistoryDataLoadedFromStore() override;
 
   scoped_ptr<HistoryData> data_;
   scoped_refptr<HistoryDataStore> store_;