Multicast DNS implementation (initial)

net/dns/mdns_client.cc

+// Copyright (c) 2013 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 "net/dns/mdns_client.h"
+#include "net/dns/mdns_client_impl.h"
+
+namespace net {
+
+static MDnsClient* g_instance = NULL;
+
+MDnsClient* MDnsClient::GetInstance() {
+  if (!g_instance) {
+    g_instance = new MDnsClientImpl();
+  }
+
+  return g_instance;
+}
+
+void MDnsClient::SetInstance(MDnsClient* instance) {
+  g_instance = instance;
+}
+}