Add the ability for MDnsListener to actively refresh records

net/dns/mdns_cache.h

 // Copyright (c) 2013 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_MDNS_CACHE_H_
 #define NET_DNS_MDNS_CACHE_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 37 matching lines @@
     unsigned type_;
     std::string name_;
     std::string optional_;
   };
 
   typedef base::Callback<void(const RecordParsed*)> RecordRemovedCallback;
 
   enum UpdateType {
     RecordAdded,
     RecordChanged,
+    RecordRemoved,
     NoChange
   };
 
   MDnsCache();
   ~MDnsCache();
 
   // Return value indicates whether the record was added, changed
   // (existed previously with different value) or not changed (existed
   // previously with same value).
   UpdateType UpdateDnsRecord(scoped_ptr<const RecordParsed> record);
@@ skipping 42 matching lines @@
   RecordMap mdns_cache_;
 
   base::Time next_expiration_;
 
   DISALLOW_COPY_AND_ASSIGN(MDnsCache);
 };
 
 }  // namespace net
 
 #endif  // NET_DNS_MDNS_CACHE_H_