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

chrome/browser/metrics/variations/variations_service.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 "chrome/browser/metrics/variations/variations_service.h"
 
 #include <set>
 
 #include "base/base64.h"
 #include "base/build_time.h"
@@ skipping 159 matching lines @@
   create_trials_from_seed_called_ = called;
 }
 
 void VariationsService::DoActualFetch() {
   pending_seed_request_.reset(net::URLFetcher::Create(
       variations_server_url_, net::URLFetcher::GET, this));
   pending_seed_request_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                                       net::LOAD_DO_NOT_SAVE_COOKIES);
   pending_seed_request_->SetRequestContext(
       g_browser_process->system_request_context());
-  pending_seed_request_->SetMaxRetries(kMaxRetrySeedFetch);
+  pending_seed_request_->SetMaxRetriesOn5xx(kMaxRetrySeedFetch);
   if (!variations_serial_number_.empty()) {
     pending_seed_request_->AddExtraRequestHeader("If-Match:" +
                                                  variations_serial_number_);
   }
   pending_seed_request_->Start();
 
   last_request_started_time_ = base::TimeTicks::Now();
 }
 
 void VariationsService::FetchVariationsSeed() {
@@ skipping 320 matching lines @@
                                       variation_id);
     }
   }
 
   trial->SetForced();
   if (IsStudyExpired(study, reference_date))
     trial->Disable();
 }
 
 }  // namespace chrome_variations