face: ProtocolFactory registry

refs #3904

Change-Id: Ic7c8b3d6138b7c27d4189a2e15cc646055ad1294
diff --git a/daemon/face/udp-factory.hpp b/daemon/face/udp-factory.hpp
index 7ec42b3..1e1a6ab 100644
--- a/daemon/face/udp-factory.hpp
+++ b/daemon/face/udp-factory.hpp
@@ -53,6 +53,9 @@
     }
   };
 
+  static const std::string&
+  getId();
+
   /** \brief process face_system.udp config section
    */
   void