Add support for mapping node tree on the client.

mojo/services/public/cpp/view_manager/util.h

+// Copyright 2014 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.
+
+#ifndef MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_UTIL_H_
+#define MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_UTIL_H_
+
+#include "mojo/services/public/cpp/view_manager/view_manager_types.h"
+
+namespace mojo {
+namespace services {
+namespace view_manager {
+
+inline uint16_t HiWord(uint32_t id) {
+  return static_cast<uint16_t>((id >> 16) & 0xFFFF);
+}
+
+inline uint16_t LoWord(uint32_t id) {
+  return static_cast<uint16_t>(id & 0xFFFF);
+}
+
+}  // namespace view_manager
+}  // namespace services
+}  // namespace mojo
+
+#endif  // MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_UTIL_H_