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

net/base/dnsrr_resolver.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/dnsrr_resolver.h"
 
 #if defined(OS_POSIX)
 #include <netinet/in.h>
 #include <resolv.h>
 #endif
@@ skipping 491 matching lines @@
 
 // An RRResolverJob is a one-to-one counterpart of an RRResolverWorker. It
 // lives only on the DnsRRResolver's origin message loop.
 class RRResolverJob {
  public:
   explicit RRResolverJob(RRResolverWorker* worker)
       : worker_(worker) {
   }
 
   ~RRResolverJob() {
-    if (worker_) {
-      worker_->Cancel();
-      worker_ = NULL;
-      PostAll(ERR_ABORTED, NULL);
-    }
+    Cancel(ERR_ABORTED);
   }
 
   void AddHandle(RRResolverHandle* handle) {
     handles_.push_back(handle);
   }
 
   void HandleResult(int result, const RRResponse& response) {
     worker_ = NULL;
     PostAll(result, &response);
   }
 
+  void Cancel(int result) {
+    if (worker_) {
+      worker_->Cancel();
+      worker_ = NULL;
+      PostAll(result, NULL);
+    }
+  }
+
  private:
   void PostAll(int result, const RRResponse* response) {
     std::vector<RRResolverHandle*> handles;
     handles_.swap(handles);
 
     for (std::vector<RRResolverHandle*>::iterator
          i = handles.begin(); i != handles.end(); i++) {
       (*i)->Post(result, response);
       // Post() causes the RRResolverHandle to delete itself.
     }
@@ skipping 98 matching lines @@
 }
 
 void DnsRRResolver::OnIPAddressChanged() {
   DCHECK(CalledOnValidThread());
   DCHECK(!in_destructor_);
 
   std::map<std::pair<std::string, uint16>, RRResolverJob*> inflight;
   inflight.swap(inflight_);
   cache_.clear();
 
+  std::map<std::pair<std::string, uint16>, RRResolverJob*>::iterator it;
+  for (it = inflight.begin(); it != inflight.end(); ++it)
+    it->second->Cancel(ERR_NETWORK_CHANGED);
   STLDeleteValues(&inflight);
 }
 
 // HandleResult is called on the origin message loop.
 void DnsRRResolver::HandleResult(const std::string& name, uint16 rrtype,
                                  int result, const RRResponse& response) {
   DCHECK(CalledOnValidThread());
 
   const std::pair<std::string, uint16> key(std::make_pair(name, rrtype));
 
@@ skipping 24 matching lines @@
     return;
   }
   RRResolverJob* job = j->second;
   inflight_.erase(j);
 
   job->HandleResult(result, response);
   delete job;
 }
 
 }  // namespace net