Standardize usage of virtual/override/final specifiers.

ash/system/tray_accessibility.cc

 // Copyright (c) 2012 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.
 
 #include "ash/system/tray_accessibility.h"
 
 #include "ash/accessibility_delegate.h"
 #include "ash/metrics/user_metrics_recorder.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
@@ skipping 66 matching lines @@
     ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
     SetImage(bundle.GetImageNamed(IDR_AURA_UBER_TRAY_ACCESSIBILITY_DARK).
                     ToImageSkia());
     base::string16 label = bundle.GetLocalizedString(
         IDS_ASH_STATUS_TRAY_ACCESSIBILITY);
     SetLabel(label);
     SetAccessibleName(label);
     set_id(test::kAccessibilityTrayItemViewId);
   }
 
-  virtual ~DefaultAccessibilityView() {
-  }
+  ~DefaultAccessibilityView() override {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DefaultAccessibilityView);
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 // ash::tray::AccessibilityPopupView
 
 AccessibilityPopupView::AccessibilityPopupView(SystemTrayItem* owner,
                                                uint32 enabled_state_bits)
@@ skipping 333 matching lines @@
     if (detailed_popup_)
       detailed_popup_->GetWidget()->Close();
     if (detailed_menu_)
       detailed_menu_->GetWidget()->Close();
   }
 
   previous_accessibility_state_ = accessibility_state;
 }
 
 }  // namespace ash