Hide icons in message center on lock screen

ui/message_center/views/message_center_button_bar.cc

Index: ui/message_center/views/message_center_button_bar.cc
diff --git a/ui/message_center/views/message_center_button_bar.cc b/ui/message_center/views/message_center_button_bar.cc
index fb86d939ed5e603b0eb503e451e66b2c99a7bf10..94778e9f4fae675e957ccd8e4e3e323dc162becf 100644
--- a/ui/message_center/views/message_center_button_bar.cc
+++ b/ui/message_center/views/message_center_button_bar.cc
@@ -242,7 +242,7 @@ void MessageCenterButtonBar::ViewVisibilityChanged() {
                     0);
 #endif
 
-  layout->StartRow(0, 0);
+  layout->StartRowWithHeight(0, 0, kButtonSize);
   if (title_arrow_->visible())
     layout->AddView(title_arrow_);
   layout->AddView(notification_label_);
@@ -280,6 +280,17 @@ void MessageCenterButtonBar::SetTitle(const base::string16& title) {
   notification_label_->SetText(title);
 }
 
+void MessageCenterButtonBar::SetButtonsVisible(bool visible) {
+  settings_button_->SetVisible(visible);
+  quiet_mode_button_->SetVisible(visible);
+
+  if (close_all_button_)
+    close_all_button_->SetVisible(visible);
+
+  ViewVisibilityChanged();
+  Layout();
+}
+
 void MessageCenterButtonBar::ChildVisibilityChanged(views::View* child) {
   InvalidateLayout();
 }