Standardize usage of virtual/override/final specifiers.

ash/system/tray/tray_popup_item_container.h

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_SYSTEM_TRAY_TRAY_POPUP_ITEM_CONTAINER_H_
 #define ASH_SYSTEM_TRAY_TRAY_POPUP_ITEM_CONTAINER_H_
 
 #include "ui/views/view.h"
 
 namespace ash {
 
 // A view which can optionally change the background color when a mouse is
 // hovering or a user is interacting via touch.
 class TrayPopupItemContainer : public views::View {
  public:
   TrayPopupItemContainer(views::View* view,
                          bool change_background,
                          bool draw_border);
 
-  virtual ~TrayPopupItemContainer();
+  ~TrayPopupItemContainer() override;
 
   bool active() {
     return active_;
   }
 
  private:
   // Sets whether the active background is to be used, and triggers a paint.
   void SetActive(bool active);
 
   // views::View:
-  virtual void ChildVisibilityChanged(views::View* child) override;
-  virtual void ChildPreferredSizeChanged(views::View* child) override;
-  virtual void OnMouseEntered(const ui::MouseEvent& event) override;
-  virtual void OnMouseExited(const ui::MouseEvent& event) override;
-  virtual void OnGestureEvent(ui::GestureEvent* event) override;
-  virtual void OnPaintBackground(gfx::Canvas* canvas) override;
+  void ChildVisibilityChanged(views::View* child) override;
+  void ChildPreferredSizeChanged(views::View* child) override;
+  void OnMouseEntered(const ui::MouseEvent& event) override;
+  void OnMouseExited(const ui::MouseEvent& event) override;
+  void OnGestureEvent(ui::GestureEvent* event) override;
+  void OnPaintBackground(gfx::Canvas* canvas) override;
 
   // True if either a mouse is hovering over this view, or if a user has touched
   // down.
   bool active_;
 
   // True if mouse hover and touch feedback can alter the background color of
   // the container.
   bool change_background_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayPopupItemContainer);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_TRAY_POPUP_ITEM_CONTAINER_H_