Do not use generated Listener interface and prefer a CompositeListeners,
which allow more flexible dispatch.
Change-Id: I7848c91eb80900ed1bdde70f2f75c13325a41680 Signed-off-by: Robert Varga <robert.varga@pantheon.tech> Signed-off-by: Sangwook Ha <sangwook.ha@verizon.com>