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..41b40187a52a80ec3a3643e1d2ea08de0a46bdbd 100644
--- a/ui/message_center/views/message_center_button_bar.h
+++ b/ui/message_center/views/message_center_button_bar.h
@@ -43,6 +43,8 @@ class MessageCenterButtonBar : public views::View,
   void SetCloseAllButtonEnabled(bool enabled);
 
   MESSAGE_CENTER_EXPORT views::Button* GetCloseAllButtonForTest() const;
+  MESSAGE_CENTER_EXPORT views::Button* GetSettingsButtonForTest() const;
+  MESSAGE_CENTER_EXPORT views::Button* GetQuietModeButtonForTest() const;
 
   // Sometimes we shouldn't see the back arrow (not in settings).
   void SetBackArrowVisible(bool visible);
@@ -50,6 +52,8 @@ 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.