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

chrome/browser/extensions/api/idle/idle_manager.h

Index: chrome/browser/extensions/api/idle/idle_manager.h
diff --git a/chrome/browser/extensions/api/idle/idle_manager.h b/chrome/browser/extensions/api/idle/idle_manager.h
index 8e96e27cbcbf7da56426c52696c4aacbf81fa685..a5a2bfc2d771687eea8cd52985dd4adb784bb60f 100644
--- a/chrome/browser/extensions/api/idle/idle_manager.h
+++ b/chrome/browser/extensions/api/idle/idle_manager.h
@@ -69,22 +69,21 @@ class IdleManager : public ExtensionRegistryObserver,
   };
 
   explicit IdleManager(Profile* profile);
-  virtual ~IdleManager();
+  ~IdleManager() override;
 
   void Init();
 
   // KeyedService implementation.
-  virtual void Shutdown() override;
+  void Shutdown() override;
 
   // ExtensionRegistryObserver implementation.
-  virtual void OnExtensionUnloaded(
-      content::BrowserContext* browser_context,
-      const Extension* extension,
-      UnloadedExtensionInfo::Reason reason) override;
+  void OnExtensionUnloaded(content::BrowserContext* browser_context,
+                           const Extension* extension,
+                           UnloadedExtensionInfo::Reason reason) override;
 
   // EventRouter::Observer implementation.
-  virtual void OnListenerAdded(const EventListenerInfo& details) override;
-  virtual void OnListenerRemoved(const EventListenerInfo& details) override;
+  void OnListenerAdded(const EventListenerInfo& details) override;
+  void OnListenerRemoved(const EventListenerInfo& details) override;
 
   void QueryState(int threshold, QueryStateCallback notify);
   void SetThreshold(const std::string& extension_id, int threshold);