Remove NoNotificationMessageView from empty message center

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 3d7420549eee77fc218a8be1c531da18b4288e9a..8dc07d69ff45e5b6d3974f33a13fa752910fd097 100644
--- a/ui/message_center/views/message_center_button_bar.h
+++ b/ui/message_center/views/message_center_button_bar.h
@@ -39,7 +39,7 @@ class MessageCenterButtonBar : public views::View,
 
   // Enables or disables all of the buttons in the center.  This is used to
   // prevent user clicks during the close-all animation.
-  virtual void SetAllButtonsEnabled(bool enabled);
+  void SetSettingsAndQuietModeButtonsEnabled(bool enabled);
 
   // Sometimes we shouldn't see the close-all button.
   void SetCloseAllButtonEnabled(bool enabled);