HostResolver supports optional CNAME lookups.

net/base/address_list.cc

Index: net/base/address_list.cc
diff --git a/net/base/address_list.cc b/net/base/address_list.cc
index d1624be44463cc1df2ee447d97b40c625f4398bf..55a599200837a218a063847a19842f4808c10ee8 100644
--- a/net/base/address_list.cc
+++ b/net/base/address_list.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 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.
 
@@ -133,6 +133,14 @@ int AddressList::GetPort() const {
   return ntohs(*port_field);
 }
 
+bool AddressList::GetCanonicalName(std::string* canonical_name) const {
+  DCHECK(canonical_name);
+  if (!data_->head || !data_->head->ai_canonname)
+    return false;
+  canonical_name->assign(data_->head->ai_canonname);
+  return true;
+}
+
 void AddressList::SetFrom(const AddressList& src, int port) {
   if (src.GetPort() == port) {
     // We can reference the data from |src| directly.