Update StickyKeys overlay to show or hide AltGr depending on the

ash/sticky_keys/sticky_keys_overlay.cc

Index: ash/sticky_keys/sticky_keys_overlay.cc
diff --git a/ash/sticky_keys/sticky_keys_overlay.cc b/ash/sticky_keys/sticky_keys_overlay.cc
index 4d32f0328bf0c70875ebdeb781b9266b3a1a3b96..e91caf4ab8753a552014bf697d947a4de0fbe240 100644
--- a/ash/sticky_keys/sticky_keys_overlay.cc
+++ b/ash/sticky_keys/sticky_keys_overlay.cc
@@ -130,6 +130,8 @@ class StickyKeysOverlayView : public views::WidgetDelegateView {
 
   StickyKeyState GetKeyState(ui::EventFlags modifier);
 
+  void SetModifierVisible(ui::EventFlags modifier, bool visible);
+
  private:
   void AddKeyLabel(ui::EventFlags modifier, const std::string& key_label);
 
@@ -191,6 +193,13 @@ StickyKeyState StickyKeysOverlayView::GetKeyState(ui::EventFlags modifier) {
   return it->second->state();
 }
 
+void StickyKeysOverlayView::SetModifierVisible(ui::EventFlags modifier,
+                                               bool visible) {
+  ModifierLabelMap::iterator it = modifier_label_map_.find(modifier);
+  DCHECK(it != modifier_label_map_.end());
+  it->second->SetVisible(visible);
+}
+
 void StickyKeysOverlayView::AddKeyLabel(ui::EventFlags modifier,
                                         const std::string& key_label) {
   StickyKeyOverlayLabel* label = new StickyKeyOverlayLabel(key_label);
@@ -257,6 +266,12 @@ void StickyKeysOverlay::Show(bool visible) {
   overlay_widget_->GetLayer()->SetTransform(gfx::Transform());
 }
 
+void StickyKeysOverlay::SetModifierVisible(ui::EventFlags modifier,
+                                           bool visible) {
+  overlay_view_->SetModifierVisible(modifier, visible);
+  widget_size_ = overlay_view_->GetPreferredSize();
+}
+
 void StickyKeysOverlay::SetModifierKeyState(ui::EventFlags modifier,
                                             StickyKeyState state) {
   overlay_view_->SetKeyState(modifier, state);