[net/dns] Resolve AF_UNSPEC on dual-stacked systems. Sort addresses according to RFC3484.

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_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 63 matching lines @@
   const char* cur_;
 };
 
 // Buffer-holder for the DNS response allowing easy access to the header fields
 // and resource records. After reading into |io_buffer| must call InitParse to
 // position the RR parser.
 class NET_EXPORT_PRIVATE DnsResponse {
  public:
   // Possible results from ParseToAddressList.
   enum Result {
-    DNS_SUCCESS = 0,
+    DNS_PARSE_OK = 0,
     DNS_MALFORMED_RESPONSE,    // DnsRecordParser failed before the end of
                                // packet.
     DNS_MALFORMED_CNAME,       // Could not parse CNAME out of RRDATA.
     DNS_NAME_MISMATCH,         // Got an address but no ordered chain of CNAMEs
                                // leads there.
     DNS_SIZE_MISMATCH,         // Got an address but size does not match.
     DNS_CNAME_AFTER_ADDRESS,   // Found CNAME after an address record.
     DNS_ADDRESS_TTL_MISMATCH,  // TTL of all address records are not identical.
-    DNS_NO_ADDRESSES,          // No address records found.
+    DNS_NO_ADDRESSES,          // OBSOLETE. No longer used.
     // Only add new values here.
     DNS_PARSE_RESULT_MAX,      // Bounding value for histograms.
   };
 
   // Constructs an object with an IOBuffer large enough to read
   // one byte more than largest possible response, to detect malformed
   // responses.
   DnsResponse();
   // Constructs response from |data|. Used for testing purposes only!
   DnsResponse(const void* data, size_t length, size_t answer_offset);
@@ skipping 43 matching lines @@
   // 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_