Simplify AuthenticationMethod type and PIN hash handling.

remoting/protocol/pairing_client_authenticator.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/protocol/pairing_client_authenticator.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "remoting/base/constants.h"
 #include "remoting/base/rsa_key_pair.h"
@@ skipping 44 matching lines @@
     message->AddElement(pairing_tag);
     sent_client_id_ = true;
   }
 }
 
 void PairingClientAuthenticator::OnPinFetched(
     State initial_state,
     const SetAuthenticatorCallback& callback,
     const std::string& pin) {
   callback.Run(V2Authenticator::CreateForClient(
-      AuthenticationMethod::ApplyHashFunction(
-          AuthenticationMethod::HMAC_SHA256,
-          authentication_tag_, pin),
+      ApplySharedSecretHashFunction(HashFunction::HMAC_SHA256,
+                                    authentication_tag_, pin),
       initial_state));
 }
 
 }  // namespace protocol
 }  // namespace remoting