Hide icons in message center on lock screen

ui/message_center/views/message_center_button_bar.h

Index: ui/message_center/views/message_center_button_bar.h
diff --git a/ui/message_center/views/message_center_button_bar.h b/ui/message_center/views/message_center_button_bar.h
index 752ac231e4f5ab3ac943a6bec0623d5beaf6e09d..dc1564e2e0b07e7168839974215788848381c6c1 100644
--- a/ui/message_center/views/message_center_button_bar.h
+++ b/ui/message_center/views/message_center_button_bar.h
@@ -50,6 +50,8 @@ class MessageCenterButtonBar : public views::View,
   // Update the label of the title.
   void SetTitle(const base::string16& title);
 
+  void SetButtonsVisible(bool visible);
+
  private:
   // Updates the layout manager which can have differing configuration
   // depending on the visibility of different parts of the button bar.