Introduce ERR_NETWORK_CHANGED and allow URLFetcher to automatically retry on that error.

net/base/host_resolver_impl.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_BASE_HOST_RESOLVER_IMPL_H_
 #define NET_BASE_HOST_RESOLVER_IMPL_H_
 
 #include <map>
 
 #include "base/basictypes.h"
@@ skipping 189 matching lines @@
   Key GetEffectiveKeyForRequest(const RequestInfo& info) const;
 
   // Records the result in cache if cache is present.
   void CacheResult(const Key& key,
                    const HostCache::Entry& entry,
                    base::TimeDelta ttl);
 
   // Removes |job| from |jobs_|, only if it exists.
   void RemoveJob(Job* job);
 
-  // Aborts all in progress jobs and notifies their requests.
-  // Might start new jobs.
+  // Aborts all in progress jobs with ERR_NETWORK_CHANGED and notifies their
+  // requests. Might start new jobs.
   void AbortAllInProgressJobs();
 
   // Attempts to serve each Job in |jobs_| from the HOSTS file if we have
   // a DnsClient with a valid DnsConfig.
   void TryServingAllJobsFromHosts();
 
   // NetworkChangeNotifier::IPAddressObserver:
   virtual void OnIPAddressChanged() OVERRIDE;
 
   // NetworkChangeNotifier::DNSObserver:
@@ skipping 53 matching lines @@
   HostResolverFlags additional_resolver_flags_;
 
   NetLog* net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(HostResolverImpl);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_HOST_RESOLVER_IMPL_H_