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

chrome/browser/ui/webui/history_ui.h

Index: chrome/browser/ui/webui/history_ui.h
diff --git a/chrome/browser/ui/webui/history_ui.h b/chrome/browser/ui/webui/history_ui.h
index ae961be2fdb82f46ba16a85b215f5d89161b378c..a5593c19dffcaf2bd81292630a79c7f04596f8e3 100644
--- a/chrome/browser/ui/webui/history_ui.h
+++ b/chrome/browser/ui/webui/history_ui.h
@@ -89,10 +89,10 @@ class BrowsingHistoryHandler : public content::WebUIMessageHandler,
   };
 
   BrowsingHistoryHandler();
-  virtual ~BrowsingHistoryHandler();
+  ~BrowsingHistoryHandler() override;
 
   // WebUIMessageHandler implementation.
-  virtual void RegisterMessages() override;
+  void RegisterMessages() override;
 
   // Handler for the "queryHistory" message.
   void HandleQueryHistory(const base::ListValue* args);
@@ -107,9 +107,9 @@ class BrowsingHistoryHandler : public content::WebUIMessageHandler,
   void HandleRemoveBookmark(const base::ListValue* args);
 
   // content::NotificationObserver implementation.
-  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;
 
   // Merges duplicate entries from the query results, only retaining the most
   // recent visit to a URL on a particular day. That visit contains the