We should use UserID object to identify users instead of username.

chromeos/login/auth/stub_authenticator.cc

 // Copyright 2014 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 "chromeos/login/auth/stub_authenticator.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 
@@ skipping 38 matching lines @@
       FROM_HERE, base::Bind(&StubAuthenticator::OnAuthFailure, this,
                             AuthFailure::FromNetworkAuthFailure(error)));
 }
 
 void StubAuthenticator::AuthenticateToUnlock(const UserContext& user_context) {
   AuthenticateToLogin(NULL /* not used */, user_context);
 }
 
 void StubAuthenticator::LoginAsSupervisedUser(const UserContext& user_context) {
   UserContext new_user_context = user_context;
-  new_user_context.SetUserIDHash(user_context.GetUserID() + kUserIdHashSuffix);
+  new_user_context.SetUserIDHash(user_context.GetUserID().GetUserEmail() + kUserIdHashSuffix);
   consumer_->OnAuthSuccess(new_user_context);
 }
 
 void StubAuthenticator::LoginOffTheRecord() {
   consumer_->OnOffTheRecordAuthSuccess();
 }
 
 void StubAuthenticator::LoginAsPublicSession(const UserContext& user_context) {
   UserContext logged_in_user_context = user_context;
   logged_in_user_context.SetIsUsingOAuth(false);
-  logged_in_user_context.SetUserIDHash(logged_in_user_context.GetUserID() +
+  logged_in_user_context.SetUserIDHash(logged_in_user_context.GetUserID().GetUserEmail() +
                                        kUserIdHashSuffix);
   consumer_->OnAuthSuccess(logged_in_user_context);
 }
 
-void StubAuthenticator::LoginAsKioskAccount(const std::string& app_user_id,
+void StubAuthenticator::LoginAsKioskAccount(const user_manager::UserID& app_user_id,
                                             bool use_guest_mount) {
   UserContext user_context(expected_user_context_.GetUserID());
   user_context.SetIsUsingOAuth(false);
-  user_context.SetUserIDHash(expected_user_context_.GetUserID() +
+  user_context.SetUserIDHash(expected_user_context_.GetUserID().GetUserEmail() +
                              kUserIdHashSuffix);
   consumer_->OnAuthSuccess(user_context);
 }
 
 void StubAuthenticator::OnAuthSuccess() {
   // If we want to be more like the real thing, we could save the user ID
   // in AuthenticateToLogin, but there's not much of a point.
   UserContext user_context(expected_user_context_);
-  user_context.SetUserIDHash(expected_user_context_.GetUserID() +
+  user_context.SetUserIDHash(expected_user_context_.GetUserID().GetUserEmail() +
                              kUserIdHashSuffix);
   consumer_->OnAuthSuccess(user_context);
 }
 
 void StubAuthenticator::OnAuthFailure(const AuthFailure& failure) {
   consumer_->OnAuthFailure(failure);
 }
 
 void StubAuthenticator::RecoverEncryptedData(const std::string& old_password) {
 }
 
 void StubAuthenticator::ResyncEncryptedData() {
 }
 
 void StubAuthenticator::SetExpectedCredentials(
     const UserContext& user_context) {
   expected_user_context_ = user_context;
 }
 
 StubAuthenticator::~StubAuthenticator() {
 }
 
 }  // namespace chromeos