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

ash/display/display_change_observer_chromeos.h

Index: ash/display/display_change_observer_chromeos.h
diff --git a/ash/display/display_change_observer_chromeos.h b/ash/display/display_change_observer_chromeos.h
index ebb9e8ee4aba1af57f3e039d5990d8c823e62c06..a32afc5ac897919fd385369e6a4d181f146bb645 100644
--- a/ash/display/display_change_observer_chromeos.h
+++ b/ash/display/display_change_observer_chromeos.h
@@ -35,24 +35,24 @@ class DisplayChangeObserver : public ui::DisplayConfigurator::StateController,
       const ui::DisplayConfigurator::DisplayState& output);
 
   DisplayChangeObserver();
-  virtual ~DisplayChangeObserver();
+  ~DisplayChangeObserver() override;
 
   // ui::DisplayConfigurator::StateController overrides:
-  virtual ui::MultipleDisplayState GetStateForDisplayIds(
+  ui::MultipleDisplayState GetStateForDisplayIds(
       const std::vector<int64>& outputs) const override;
-  virtual bool GetResolutionForDisplayId(int64 display_id,
-                                         gfx::Size* size) const override;
+  bool GetResolutionForDisplayId(int64 display_id,
+                                 gfx::Size* size) const override;
 
   // Overriden from ui::DisplayConfigurator::Observer:
-  virtual void OnDisplayModeChanged(
+  void OnDisplayModeChanged(
       const ui::DisplayConfigurator::DisplayStateList& outputs) override;
 
   // Overriden from ui::InputDeviceEventObserver:
-  virtual void OnTouchscreenDeviceConfigurationChanged() override;
-  virtual void OnKeyboardDeviceConfigurationChanged() override;
+  void OnTouchscreenDeviceConfigurationChanged() override;
+  void OnKeyboardDeviceConfigurationChanged() override;
 
   // Overriden from ShellObserver:
-  virtual void OnAppTerminating() override;
+  void OnAppTerminating() override;
 
   // Exposed for testing.
   ASH_EXPORT static float FindDeviceScaleFactor(float dpi);