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..44bd17d34359841a22db225133cef2880abddc8b
--- /dev/null
+++ b/ash/login/views/lock_screen.cc
@@ -0,0 +1,18 @@
+// 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/lock_contents_view.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+
+void ShowLockScreenInWidget(views::Widget* widget) {
+  views::View* contents = new LockContentsView();
+  widget->SetContentsView(contents);
+  widget->Show();
+}
+
+}  // namespace ash