replace OVERRIDE and FINAL with override and final in ash/

ash/wm/screen_dimmer.h

Index: ash/wm/screen_dimmer.h
diff --git a/ash/wm/screen_dimmer.h b/ash/wm/screen_dimmer.h
index 1d6e205d887b7217614356051d12695197ce5f95..489b93345beb837493ec761138d175d2d48e6dc5 100644
--- a/ash/wm/screen_dimmer.h
+++ b/ash/wm/screen_dimmer.h
@@ -47,7 +47,7 @@ class ASH_EXPORT ScreenDimmer : public aura::WindowObserver {
   // aura::WindowObserver overrides:
   virtual void OnWindowBoundsChanged(aura::Window* root_window,
                                      const gfx::Rect& old_bounds,
-                                     const gfx::Rect& new_bounds) OVERRIDE;
+                                     const gfx::Rect& new_bounds) override;
 
  private:
   friend class TestApi;