Validate incoming window properties.

ash/public/cpp/shelf_types.cc

Index: ash/public/cpp/shelf_types.cc
diff --git a/ash/public/cpp/shelf_types.cc b/ash/public/cpp/shelf_types.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fe51e3b7479e602e5466ea63f722080dab4c1c36
--- /dev/null
+++ b/ash/public/cpp/shelf_types.cc
@@ -0,0 +1,15 @@
+// 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 i) {
+  return i == TYPE_APP_PANEL || i == TYPE_APP_SHORTCUT || i == TYPE_APP_LIST ||
+         i == TYPE_BROWSER_SHORTCUT || i == TYPE_APP || i == TYPE_DIALOG ||
+         i == TYPE_UNDEFINED;
+}
+
+}  // namespace ash