cros: Make sure views-based lock screen is destroyed after it is dismissed.

ash/login/mock_lock_screen_client.cc

 // Copyright 2017 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 "ash/login/mock_lock_screen_client.h"
 
 #include "ash/login/lock_screen_controller.h"
 #include "ash/shell.h"
 
 namespace ash {
 
 MockLockScreenClient::MockLockScreenClient() : binding_(this) {}
 
 MockLockScreenClient::~MockLockScreenClient() = default;
 
 mojom::LockScreenClientPtr MockLockScreenClient::CreateInterfacePtrAndBind() {
   return binding_.CreateInterfacePtrAndBind();
 }
 
+void MockLockScreenClient::AuthenticateUser(const AccountId& account_id,
+                                            const std::string& password,
+                                            bool authenticated_by_pin,
+                                            AuthenticateUserCallback callback) {
+  AuthenticateUser_(account_id, password, authenticated_by_pin, callback);
+  std::move(callback).Run(authenticate_user_callback_result_);
+}
+
 std::unique_ptr<MockLockScreenClient> BindMockLockScreenClient() {
   LockScreenController* lock_screen_controller =
       Shell::Get()->lock_screen_controller();
   auto lock_screen_client = base::MakeUnique<MockLockScreenClient>();
   lock_screen_controller->SetClient(
       lock_screen_client->CreateInterfacePtrAndBind());
   return lock_screen_client;
 }
 
 }  // namespace ash