Add a mechanism to disable IPv6....

net/base/address_family.h

+// Copyright (c) 2009 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 NET_BASE_ADDRESS_FAMILY_H_
+#define NET_BASE_ADDRESS_FAMILY_H_
+
+namespace net {
+
+// Enum wrapper around the address family types supported by host resolver
+// procedures. These correspond with AF_UNSPEC and AF_INET.
+enum AddressFamily {
+  ADDRESS_FAMILY_UNSPECIFIED,
+  ADDRESS_FAMILY_IPV4_ONLY,
+};
+
+}  // namesapce net
+
+#endif  // NET_BASE_ADDRESS_FAMILY_H_