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

net/base/host_resolver_impl.cc

 // 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.
 
 #include "net/base/host_resolver_impl.h"
 
 #if defined(OS_WIN)
 #include <Winsock2.h>
 #elif defined(OS_POSIX)
 #include <netdb.h>
@@ skipping 1249 matching lines @@
     if (num_active_requests() > 0) {
       UpdatePriority();
     } else {
       // If we were called from a Request's callback within CompleteRequests,
       // that Request could not have been cancelled, so num_active_requests()
       // could not be 0. Therefore, we are not in CompleteRequests().
       CompleteRequestsWithError(OK /* cancelled */);
     }
   }
 
-  // Called from AbortAllInProgressJobs. Completes all requests as aborted
-  // and destroys the job.
+  // Called from AbortAllInProgressJobs. Completes all requests and destroys
+  // the job. This currently assumes the abort is due to a network change.
   void Abort() {
     DCHECK(is_running());
-    CompleteRequestsWithError(ERR_ABORTED);
+    CompleteRequestsWithError(ERR_NETWORK_CHANGED);
   }
 
   // If DnsTask present, abort it and fall back to ProcTask.
   void AbortDnsTask() {
     if (dns_task_) {
       dns_task_.reset();
       dns_task_error_ = OK;
       StartProcTask();
     }
   }
@@ skipping 239 matching lines @@
 
     DCHECK(!requests_.empty());
 
     if (entry.error == OK) {
       // Record this histogram here, when we know the system has a valid DNS
       // configuration.
       UMA_HISTOGRAM_BOOLEAN("AsyncDNS.HaveDnsConfig",
                             resolver_->received_dns_config_);
     }
 
-    bool did_complete = (entry.error != ERR_ABORTED) &&
+    bool did_complete = (entry.error != ERR_NETWORK_CHANGED) &&
                         (entry.error != ERR_HOST_RESOLVER_QUEUE_TOO_LARGE);
     if (did_complete)
       resolver_->CacheResult(key_, entry, ttl);
 
     // Complete all of the requests that were attached to the job.
     for (RequestsList::const_iterator it = requests_.begin();
          it != requests_.end(); ++it) {
       Request* req = *it;
 
       if (req->was_canceled())
@@ skipping 620 matching lines @@
   }
   DnsConfig dns_config;
   NetworkChangeNotifier::GetDnsConfig(&dns_config);
   dns_client_->SetConfig(dns_config);
   num_dns_failures_ = 0;
   if (dns_config.IsValid())
     UMA_HISTOGRAM_BOOLEAN("AsyncDNS.DnsClientEnabled", true);
 }
 
 }  // namespace net