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

net/dns/dns_response.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_RESPONSE_H_
 #define NET_DNS_DNS_RESPONSE_H_
 #pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/string_piece.h"
+#include "base/time.h"
 #include "net/base/net_export.h"
 #include "net/base/net_util.h"
 
 namespace net {
 
+class AddressList;
 class DnsQuery;
 class IOBufferWithSize;
 
 namespace dns_protocol {
 struct Header;
 }
 
 // Parsed resource record.
 struct NET_EXPORT_PRIVATE DnsResourceRecord {
   DnsResourceRecord();
@@ skipping 80 matching lines @@
   uint16 qtype() const;
 
   // Returns qname in dotted format.
   std::string GetDottedName() const;
 
   // Returns an iterator to the resource records in the answer section.
   // The iterator is valid only in the scope of the DnsResponse.
   // This operation is idempotent.
   DnsRecordParser Parser() const;
 
+  // Extracts an AddressList from this response. Returns true if succeeded.
+  bool ParseAddressList(AddressList* addr_list, base::TimeDelta* ttl) const;

[mmenke, 2012/02/14 18:46:00]

nit:  Suggest you rename this function to ParseAddresses or AsAddressList or
CreateAddressList or something.  Want to make it clearer from its name that it
is not parsing the AddressList that's an argument, but it's parsing its contents
as an address.

+
  private:
   // Convenience for header access.
   const dns_protocol::Header* header() const;
 
   // Buffer into which response bytes are read.
   scoped_refptr<IOBufferWithSize> io_buffer_;
 
   // Iterator constructed after InitParse positioned at the answer section.
   // It is never updated afterwards, so can be used in accessors.
   DnsRecordParser parser_;
 
   DISALLOW_COPY_AND_ASSIGN(DnsResponse);
 };
 
 }  // namespace net
 
 #endif  // NET_DNS_DNS_RESPONSE_H_