Fix stupid mistake to use a private class in public API.

Also a preparation the be able to implement the next commit.

Change-Id: Iaeba54e5c1cfe97178e28fcc3fe72f9623f10bc6
Reviewed-by: Niels Weber <niels.weber@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@digia.com>