Update StickyKeys overlay to show or hide AltGr depending on the

ash/sticky_keys/sticky_keys_overlay.h

Index: ash/sticky_keys/sticky_keys_overlay.h
diff --git a/ash/sticky_keys/sticky_keys_overlay.h b/ash/sticky_keys/sticky_keys_overlay.h
index 88d195a7843e179f4686418c688fbf3682a6f23d..74d082afe55914fdf245fd8571f2e51e72f25bfb 100644
--- a/ash/sticky_keys/sticky_keys_overlay.h
+++ b/ash/sticky_keys/sticky_keys_overlay.h
@@ -36,6 +36,8 @@ class ASH_EXPORT StickyKeysOverlay : public ui::LayerAnimationObserver {
   // Shows or hides the overlay.
   void Show(bool visible);
 
+  void SetModifierVisible(ui::EventFlags modifier, bool visible);
+
   // Updates the overlay with the current state of a sticky key modifier.
   void SetModifierKeyState(ui::EventFlags modifier,
                            StickyKeyState state);