[cros] user_manager component - move UserManagerBase and UserManager

chrome/browser/chromeos/login/users/scoped_user_manager_enabler.cc

+// Copyright 2014 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/users/scoped_user_manager_enabler.h"
+
+#include "components/user_manager/user_manager.h"
+
+namespace chromeos {
+
+ScopedUserManagerEnabler::ScopedUserManagerEnabler(
+    user_manager::UserManager* user_manager) {
+  if (user_manager::UserManager::GetForTesting())
+    user_manager::UserManager::GetForTesting()->Shutdown();
+
+  previous_user_manager_ =
+      user_manager::UserManager::SetForTesting(user_manager);
+}
+
+ScopedUserManagerEnabler::~ScopedUserManagerEnabler() {
+  // Shutdown and destroy current UserManager instance that we track.
+  user_manager::UserManager::Get()->Shutdown();
+  delete user_manager::UserManager::Get();
+  user_manager::UserManager::SetInstance(NULL);
+
+  user_manager::UserManager::SetForTesting(previous_user_manager_);
+}
+
+}  // namespace chromeos