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

chrome/browser/ui/ash/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 "chrome/browser/ui/ash/lock_screen_client.h"
 
 #include "ash/public/interfaces/constants.mojom.h"
 #include "chrome/browser/chromeos/login/lock/screen_locker.h"
 #include "content/public/common/service_manager_connection.h"
 #include "services/service_manager/public/cpp/connector.h"
@@ skipping 18 matching lines @@
   g_instance = nullptr;
 }
 
 // static
 LockScreenClient* LockScreenClient::Get() {
   return g_instance;
 }
 
 void LockScreenClient::AuthenticateUser(const AccountId& account_id,
                                         const std::string& hashed_password,
-                                        bool authenticated_by_pin) {
+                                        bool authenticated_by_pin,
+                                        AuthenticateUserCallback callback) {
   // TODO(xiaoyinh): Complete the implementation below.
   // It should be similar as SigninScreenHandler::HandleAuthenticateUser.
   chromeos::UserContext user_context(account_id);
   chromeos::Key key(chromeos::Key::KEY_TYPE_SALTED_SHA256_TOP_HALF,
                     std::string(), hashed_password);
   user_context.SetKey(key);
   user_context.SetIsUsingPin(authenticated_by_pin);
-  chromeos::ScreenLocker::default_screen_locker()->Authenticate(user_context);
+  chromeos::ScreenLocker::default_screen_locker()->Authenticate(
+      user_context, std::move(callback));
+}
+
+void LockScreenClient::ShowLockScreen(
+    ash::mojom::LockScreen::ShowLockScreenCallback on_shown) {
+  lock_screen_->ShowLockScreen(std::move(on_shown));
 }
 
 void LockScreenClient::ShowErrorMessage(int32_t login_attempts,
                                         const std::string& error_text,
                                         const std::string& help_link_text,
                                         int32_t help_topic_id) {
   lock_screen_->ShowErrorMessage(login_attempts, error_text, help_link_text,
                                  help_topic_id);
 }
 
 void LockScreenClient::ClearErrors() {
   lock_screen_->ClearErrors();
 }