Remove first_message argument from AuthenticatorFactory::Create().

remoting/protocol/it2me_host_authenticator_factory.cc

Index: remoting/protocol/it2me_host_authenticator_factory.cc
diff --git a/remoting/protocol/it2me_host_authenticator_factory.cc b/remoting/protocol/it2me_host_authenticator_factory.cc
index 695b1b59ccbe7c44092843385ab7e57e202c022b..9ccf297592f644c9534c0449956f4d05061e5bcd 100644
--- a/remoting/protocol/it2me_host_authenticator_factory.cc
+++ b/remoting/protocol/it2me_host_authenticator_factory.cc
@@ -27,8 +27,7 @@ It2MeHostAuthenticatorFactory::~It2MeHostAuthenticatorFactory() {}
 
 scoped_ptr<Authenticator> It2MeHostAuthenticatorFactory::CreateAuthenticator(
     const std::string& local_jid,
-    const std::string& remote_jid,
-    const buzz::XmlElement* first_message) {
+    const std::string& remote_jid) {
   // Check the client domain policy.
   if (!required_client_domain_.empty()) {
     std::string client_username = remote_jid;