Message center re-organized

ui/message_center/message_center_tray.h

Index: ui/message_center/message_center_tray.h
diff --git a/ui/message_center/message_center_tray.h b/ui/message_center/message_center_tray.h
index 7c0986b30dd0958ded730bd81836f0a4645160a5..03b86e9391e06a50287bf0a05d388379e375bb32 100644
--- a/ui/message_center/message_center_tray.h
+++ b/ui/message_center/message_center_tray.h
@@ -38,9 +38,14 @@ class MESSAGE_CENTER_EXPORT MessageCenterTray
   // not it was visible before.
   bool ShowMessageCenterBubble();
 
-  // Returns whether the message center was visible before.
+  // Hides the message center if visible and returns whether the message center
+  // was visible before.
   bool HideMessageCenterBubble();
 
+  // Marks the message center as "not visible" (this method will not hide the
+  // message center).
+  void MarkMessageCenterHidden();
+
   void ToggleMessageCenterBubble();
 
   // Causes an update if the popup bubble is already shown.