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

chrome/browser/sync/glue/extensions_activity_monitor.h

Index: chrome/browser/sync/glue/extensions_activity_monitor.h
diff --git a/chrome/browser/sync/glue/extensions_activity_monitor.h b/chrome/browser/sync/glue/extensions_activity_monitor.h
index 5ad851611382a22134fc98c1b83ebc980040c349..d8d2f4ff94b7be066d91c9f7565b8e23d48950be 100644
--- a/chrome/browser/sync/glue/extensions_activity_monitor.h
+++ b/chrome/browser/sync/glue/extensions_activity_monitor.h
@@ -20,12 +20,12 @@ namespace browser_sync {
 class ExtensionsActivityMonitor : public content::NotificationObserver {
  public:
   ExtensionsActivityMonitor();
-  virtual ~ExtensionsActivityMonitor();
+  ~ExtensionsActivityMonitor() override;
 
   // 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;
 
   const scoped_refptr<syncer::ExtensionsActivity>& GetExtensionsActivity();