face: ProtocolFactory registry

refs #3904

Change-Id: Ic7c8b3d6138b7c27d4189a2e15cc646055ad1294
diff --git a/daemon/face/tcp-factory.cpp b/daemon/face/tcp-factory.cpp
index a3028b5..a273e42 100644
--- a/daemon/face/tcp-factory.cpp
+++ b/daemon/face/tcp-factory.cpp
@@ -32,6 +32,14 @@
 namespace ip = boost::asio::ip;
 
 NFD_LOG_INIT("TcpFactory");
+NFD_REGISTER_PROTOCOL_FACTORY(TcpFactory);
+
+const std::string&
+TcpFactory::getId()
+{
+  static std::string id("tcp");
+  return id;
+}
 
 void
 TcpFactory::processConfig(OptionalConfigSection configSection,