Standardize usage of virtual/override/final specifiers.

ash/system/user/accounts_detailed_view.h

Index: ash/system/user/accounts_detailed_view.h
diff --git a/ash/system/user/accounts_detailed_view.h b/ash/system/user/accounts_detailed_view.h
index 533a2c6eb2eca9ad437f908e7e6b039ea6d17ffc..7fabcc32166aaab8fdb0560e5d961f95303cd383 100644
--- a/ash/system/user/accounts_detailed_view.h
+++ b/ash/system/user/accounts_detailed_view.h
@@ -31,18 +31,17 @@ class AccountsDetailedView : public TrayDetailsView,
                              public ash::tray::UserAccountsDelegate::Observer {
  public:
   AccountsDetailedView(TrayUser* owner, user::LoginStatus login_status);
-  virtual ~AccountsDetailedView();
+  ~AccountsDetailedView() override;
 
  private:
   // Overridden from ViewClickListener.
-  virtual void OnViewClicked(views::View* sender) override;
+  void OnViewClicked(views::View* sender) override;
 
   // Overridden from views::ButtonListener.
-  virtual void ButtonPressed(views::Button* sender,
-                             const ui::Event& event) override;
+  void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
   // Overridden from ash::tray::UserAccountsDelegate::Observer.
-  virtual void AccountListChanged() override;
+  void AccountListChanged() override;
 
   void AddHeader(user::LoginStatus login_status);
   void AddAccountList();