Validate incoming window properties.

ash/public/cpp/shelf_types.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/public/cpp/shelf_types.h"
+
+namespace ash {
+
+bool IsValidShelfItemType(int64_t type) {
+  return type == TYPE_APP_PANEL || type == TYPE_APP_SHORTCUT ||
+         type == TYPE_APP_LIST || type == TYPE_BROWSER_SHORTCUT ||
+         type == TYPE_APP || type == TYPE_DIALOG || type == TYPE_UNDEFINED;
+}
+
+}  // namespace ash