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

net/dns/dns_response.h

Index: net/dns/dns_response.h
diff --git a/net/dns/dns_response.h b/net/dns/dns_response.h
index 5ade458803b5fc21c3261fe53af28fbf27337c5a..fe80c30e4333e89ca6a5266c590a9c52554c3754 100644
--- a/net/dns/dns_response.h
+++ b/net/dns/dns_response.h
@@ -81,7 +81,7 @@ 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.
@@ -90,7 +90,7 @@ class NET_EXPORT_PRIVATE DnsResponse {
     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.
   };