Tame the proliferation of UserContext constructors

chrome/browser/chromeos/login/managed/locally_managed_user_creation_screen.cc

 // Copyright (c) 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 "chrome/browser/chromeos/login/managed/locally_managed_user_creation_screen.h"
 
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "ash/shell.h"
 #include "base/rand_util.h"
 #include "base/values.h"
@@ skipping 184 matching lines @@
   SupervisedUserAuthentication* authentication =
       UserManager::Get()->GetSupervisedUserManager()->GetAuthentication();
 
   if (authentication->GetStableSchema() ==
       SupervisedUserAuthentication::SCHEMA_PLAIN) {
     controller_.reset(new ManagedUserCreationControllerOld(this, manager_id));
   } else {
     controller_.reset(new ManagedUserCreationControllerNew(this, manager_id));
   }
 
-  ExistingUserController::current_controller()->
-      Login(UserContext(manager_id,
-                        manager_password,
-                        std::string()  /* auth_code */));
+  UserContext user_context(manager_id);
+  user_context.SetPassword(manager_password);
+  ExistingUserController::current_controller()->Login(user_context);
 }
 
 void LocallyManagedUserCreationScreen::CreateManagedUser(
     const base::string16& display_name,
     const std::string& managed_user_password) {
   DCHECK(controller_.get());
   int image;
   if (selected_image_ == User::kExternalImageIndex)
     // TODO(dzhioev): crbug/249660
     image = ManagedUserCreationController::kDummyAvatarIndex;
@@ skipping 373 matching lines @@
     selected_image_ = User::kExternalImageIndex;
   } else {
     NOTREACHED() << "Unexpected image type: " << image_type;
   }
 }
 
 void LocallyManagedUserCreationScreen::OnImageAccepted() {
 }
 
 }  // namespace chromeos