Simplify adding callbacks.

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 "chrome/browser/chromeos/cros/network_library.h"
 #include "chrome/browser/chromeos/login/existing_user_controller.h"
 #include "chrome/browser/chromeos/login/managed/locally_managed_user_controller.h"
 #include "chrome/browser/chromeos/login/screens/error_screen.h"
@@ skipping 117 matching lines @@
 
 void LocallyManagedUserCreationScreen::AbortFlow() {
   controller_->FinishCreation();
 }
 
 void LocallyManagedUserCreationScreen::FinishFlow() {
   controller_->FinishCreation();
 }
 
 void LocallyManagedUserCreationScreen::AuthenticateManager(
-    std::string& manager_id,
-    std::string& manager_password) {
+    const std::string& manager_id,
+    const std::string& manager_password) {
   // Make sure no two controllers exist at the same time.
   controller_.reset();
   controller_.reset(new LocallyManagedUserController(this));
 
   ExistingUserController::current_controller()->
       Login(UserContext(manager_id,
                         manager_password,
                         std::string()  /* auth_code */));
 }
 
 void LocallyManagedUserCreationScreen::CreateManagedUser(
-    string16& display_name,
-    std::string& managed_user_password) {
+    const string16& display_name,
+    const std::string& managed_user_password) {
   DCHECK(controller_.get());
   controller_->SetUpCreation(display_name, managed_user_password);
   controller_->StartCreation();
 }
 
 void LocallyManagedUserCreationScreen::OnManagerLoginFailure() {
   if (actor_)
     actor_->ShowManagerPasswordError();
 }
 
@@ skipping 57 matching lines @@
 
   WizardController::default_controller()->
       AdvanceToScreenWithParams(WizardController::kUserImageScreenName, params);
 }
 
 void LocallyManagedUserCreationScreen::OnCreationSuccess() {
   SelectPicture();
 }
 
 }  // namespace chromeos