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

ash/login/ui/lock_contents_view.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/ui/lock_contents_view.h"
 
 #include "ash/login/lock_screen_controller.h"
+#include "ash/login/ui/lock_screen.h"
 #include "ash/public/interfaces/user_info.mojom.h"
 #include "ash/session/session_controller.h"
 #include "ash/shell.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
 #include "ui/views/layout/box_layout.h"
 
 namespace ash {
 
@@ skipping 19 matching lines @@
                                      const ui::Event& event) {
   DCHECK(unlock_button_ == sender);
 
   // TODO: user index shouldn't be hard coded here. Complete the implementation
   // below.
   const int user_index = 0;
   const mojom::UserSession* const user_session =
       Shell::Get()->session_controller()->GetUserSession(user_index);
   Shell::Get()->lock_screen_controller()->AuthenticateUser(
       user_session->user_info->account_id, std::string(),
-      false /* authenticated_by_pin */);
+      false /* authenticated_by_pin */, base::BindOnce([](bool success) {
+        if (success)
+          DestroyLockScreen();
+      }));
 }
 
 }  // namespace ash