HostResolver supports optional CNAME lookups.

net/base/address_family.h

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 enum AddressFamily {
   ADDRESS_FAMILY_UNSPECIFIED,   // AF_UNSPEC
   ADDRESS_FAMILY_IPV4,          // AF_INET
   ADDRESS_FAMILY_IPV6,          // AF_INET6
 };
 
-}  // namesapce net
+// HostResolverFlags is a bitflag enum wrapper around the addrinfo.ai_flags
+// supported by host resolver procedures.
+enum {
+  HOST_RESOLVER_FLAGS_CANONNAME = 1 << 0, // AI_CANONNAME, 0x1
+};
+typedef int HostResolverFlags;
+
+}  // namespace net
 
 #endif  // NET_BASE_ADDRESS_FAMILY_H_