Revert of Fold UpdateModel into UpdateScreen.

chrome/browser/chromeos/login/screens/update_model.cc

+// Copyright 2015 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/screens/update_model.h"
+
+#include "chrome/browser/chromeos/login/wizard_controller.h"
+
+namespace chromeos {
+
+const char UpdateModel::kUserActionCancelUpdateShortcut[] = "cancel-update";
+const char UpdateModel::kContextKeyEstimatedTimeLeftSec[] = "time-left-sec";
+const char UpdateModel::kContextKeyShowEstimatedTimeLeft[] = "show-time-left";
+const char UpdateModel::kContextKeyUpdateMessage[] = "update-msg";
+const char UpdateModel::kContextKeyShowCurtain[] = "show-curtain";
+const char UpdateModel::kContextKeyShowProgressMessage[] = "show-progress-msg";
+const char UpdateModel::kContextKeyProgress[] = "progress";
+const char UpdateModel::kContextKeyProgressMessage[] = "progress-msg";
+const char UpdateModel::kContextKeyCancelUpdateShortcutEnabled[] =
+    "cancel-update-enabled";
+
+UpdateModel::UpdateModel(BaseScreenDelegate* base_screen_delegate)
+    : BaseScreen(base_screen_delegate, OobeScreen::SCREEN_OOBE_UPDATE) {}
+
+UpdateModel::~UpdateModel() {}
+
+}  // namespace chromeos