cros: Initial structure for views-based lock.

ash/login/views/lock_screen.cc

Index: ash/login/views/lock_screen.cc
diff --git a/ash/login/views/lock_screen.cc b/ash/login/views/lock_screen.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fb36de582bf0616fb5c94499e0986c8f3f7ed556
--- /dev/null
+++ b/ash/login/views/lock_screen.cc
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+// 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/views/lock_screen.h"
+
+#include "ash/login/views/contents_view.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+
+void ShowLockScreenInWidget(views::Widget* widget) {
+  views::View* contents = new ContentsView();
+  widget->SetContentsView(contents);
+  widget->Show();
+}
+
+}  // namespace ash