Fix the notification center label.

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 524a01f2c59d0d4b640d89fd8dd5504fa22a7e7b..583c8c30cc41dc7d654150a504f89e7f2b561c99 100644
--- a/ui/message_center/views/message_center_button_bar.h
+++ b/ui/message_center/views/message_center_button_bar.h
@@ -43,6 +43,9 @@ class MessageCenterButtonBar : public views::View,
   // Sometimes we shouldn't see the back arrow (not in settings).
   void SetBackArrowVisible(bool visible);
 
+  // Set user visible title of the Notification Tray.
+  void SetNotificationTitle(const base::string16& new_title);
+
  private:
   // Updates the layout manager which can have differing configuration
   // depending on the visibilty of different parts of the button bar.