Update {virtual,override,final} to follow C++11 style in ash.

ash/display/display_manager.h

 // 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.
 
 #ifndef ASH_DISPLAY_DISPLAY_MANAGER_H_
 #define ASH_DISPLAY_DISPLAY_MANAGER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 60 matching lines @@
   // How the second display will be used.
   // 1) EXTENDED mode extends the desktop to the second dislpay.
   // 2) MIRRORING mode copies the content of the primary display to
   //    the 2nd display. (Software Mirroring).
   enum SecondDisplayMode {
     EXTENDED,
     MIRRORING
   };
 
   DisplayManager();
-  virtual ~DisplayManager();
+  ~DisplayManager() override;
 
   DisplayLayoutStore* layout_store() {
     return layout_store_.get();
   }
 
   gfx::Screen* screen() {
     return screen_;
   }
 
   void set_delegate(Delegate* delegate) { delegate_ = delegate; }
@@ skipping 171 matching lines @@
   // Change the mirror mode.
   void SetMirrorMode(bool mirrored);
 
   // Used to emulate display change when run in a desktop environment instead
   // of on a device.
   void AddRemoveDisplay();
   void ToggleDisplayScaleFactor();
 
   // SoftwareMirroringController override:
 #if defined(OS_CHROMEOS)
-  virtual void SetSoftwareMirroring(bool enabled) override;
-  virtual bool SoftwareMirroringEnabled() const override;
+  void SetSoftwareMirroring(bool enabled) override;
+  bool SoftwareMirroringEnabled() const override;
 #endif
   bool software_mirroring_enabled() const {
     return second_display_mode_ == MIRRORING;
   };
 
   // Sets/gets second display mode.
   void SetSecondDisplayMode(SecondDisplayMode mode);
   SecondDisplayMode second_display_mode() const {
     return second_display_mode_;
   }
@@ skipping 111 matching lines @@
   gfx::Display::Rotation registered_internal_display_rotation_;
 
   base::WeakPtrFactory<DisplayManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_DISPLAY_MANAGER_H_