Add NetworkListObserver utility class.

ppapi/utility/network_list_observer.cc

+// Copyright (c) 2012 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 "ppapi/utility/network_list_observer.h"
+
+#include "ppapi/cpp/private/network_list_private.h"
+#include "ppapi/cpp/module.h"
+
+namespace pp {
+
+NetworkListObserver::NetworkListObserver(const InstanceHandle& instance)
+    : monitor_(instance, &NetworkListObserver::NetworkListCallbackHandler,
+               this) {
+}
+
+NetworkListObserver::~NetworkListObserver() {
+}
+
+// static
+void NetworkListObserver::NetworkListCallbackHandler(
+    void* user_data,
+    PP_Resource list_resource) {
+  NetworkListObserver* object =
+      static_cast<NetworkListObserver*>(user_data);
+  NetworkListPrivate list(list_resource);
+  object->OnNetworkList(list);
+  Module::Get()->core()->ReleaseResource(list_resource);
+}
+
+}  // namespace pp