[net] HostResolverImpl + DnsTransaction + DnsConfigService = Asynchronous DNS ready for experiments.

net/dns/dns_transaction.h

 // 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.
 
 #ifndef NET_DNS_DNS_TRANSACTION_H_
 #define NET_DNS_DNS_TRANSACTION_H_
 #pragma once
 
 #include <string>
 
@@ skipping 43 matching lines @@
                               const DnsResponse* response)> CallbackType;
 
   virtual ~DnsTransactionFactory() {}
 
   // Creates DnsTransaction for the given |hostname| and |qtype| (assuming
   // QCLASS is IN). |hostname| should be in the dotted form. A dot at the end
   // implies the domain name is fully-qualified and will be exempt from suffix
   // search. |hostname| should not be an IP literal.
   //
   // The transaction will run |callback| upon asynchronous completion.
-  // The source of |source_net_log| is used as source dependency in log.
+  // The |net_log| is used as the parent log.
   virtual scoped_ptr<DnsTransaction> CreateTransaction(
       const std::string& hostname,
       uint16 qtype,
       const CallbackType& callback,
-      const BoundNetLog& source_net_log) WARN_UNUSED_RESULT = 0;
+      const BoundNetLog& net_log) WARN_UNUSED_RESULT = 0;
 
   // Creates a DnsTransactionFactory which creates DnsTransactionImpl using the
   // |session|.
   static scoped_ptr<DnsTransactionFactory> CreateFactory(
       DnsSession* session) WARN_UNUSED_RESULT;
 };
 
 }  // namespace net
 
 #endif  // NET_DNS_DNS_TRANSACTION_H_