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

chrome/browser/extensions/navigation_observer.h

Index: chrome/browser/extensions/navigation_observer.h
diff --git a/chrome/browser/extensions/navigation_observer.h b/chrome/browser/extensions/navigation_observer.h
index 66686f643bc9bd358ae306a9e936da5d4d2eb85b..017acc0b577e41e7b85733c6d9dcdfe2b3e6325d 100644
--- a/chrome/browser/extensions/navigation_observer.h
+++ b/chrome/browser/extensions/navigation_observer.h
@@ -29,12 +29,13 @@ class NavigationObserver : public ExtensionInstallPrompt::Delegate,
                            public content::NotificationObserver {
  public:
   explicit NavigationObserver(Profile* profile);
-  virtual ~NavigationObserver();
+  ~NavigationObserver() override;
 
   // 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;
+
  private:
   // Registers for the NOTIFICATION_NAV_ENTRY_COMMITTED notification.
   void RegisterForNotifications();
@@ -46,8 +47,8 @@ class NavigationObserver : public ExtensionInstallPrompt::Delegate,
       content::NavigationController* nav_controller);
 
   // ExtensionInstallPrompt::Delegate callbacks used for the permissions prompt.
-  virtual void InstallUIProceed() override;
-  virtual void InstallUIAbort(bool user_initiated) override;
+  void InstallUIProceed() override;
+  void InstallUIAbort(bool user_initiated) override;
 
   content::NotificationRegistrar registrar_;