Fix crash on IP address change.

net/base/host_resolver_impl.cc

 // Copyright (c) 2010 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"
 #include "net/base/net_log.h"
 
 #include <cmath>
 #include <deque>
 
@@ skipping 665 matching lines @@
       ipv6_probe_monitoring_(false) {
   DCHECK_GT(max_jobs, 0u);
 
   // It is cumbersome to expose all of the constraints in the constructor,
   // so we choose some defaults, which users can override later.
   job_pools_[POOL_NORMAL] = new JobPool(max_jobs, 100u * max_jobs);
 
 #if defined(OS_WIN)
   EnsureWinsockInit();
 #endif
+  if (network_change_notifier_)
+    network_change_notifier_->AddObserver(this);
 }
 
 HostResolverImpl::~HostResolverImpl() {
   // Cancel the outstanding jobs. Those jobs may contain several attached
   // requests, which will also be cancelled.
   DiscardIPv6ProbeJob();
 
   for (JobMap::iterator it = jobs_.begin(); it != jobs_.end(); ++it)
     it->second->Cancel();
 
   // In case we are being deleted during the processing of a callback.
   if (cur_completing_job_)
     cur_completing_job_->Cancel();
 
+  if (network_change_notifier_)
+    network_change_notifier_->RemoveObserver(this);
+
   // Delete the job pools.
   for (size_t i = 0u; i < arraysize(job_pools_); ++i)
     delete job_pools_[i];
 }
 
 // TODO(eroman): Don't create cache entries for hostnames which are simply IP
 // address literals.
 int HostResolverImpl::Resolve(const RequestInfo& info,
                               AddressList* addresses,
                               CompletionCallback* callback,
@@ skipping 124 matching lines @@
 
 void HostResolverImpl::SetDefaultAddressFamily(AddressFamily address_family) {
   ipv6_probe_monitoring_ = false;
   DiscardIPv6ProbeJob();
   default_address_family_ = address_family;
 }
 
 void HostResolverImpl::ProbeIPv6Support() {
   DCHECK(!ipv6_probe_monitoring_);
   ipv6_probe_monitoring_ = true;
-  Flush();  // Give initial setup call.
+  OnIPAddressChanged();  // Give initial setup call.
 }
 
 void HostResolverImpl::Shutdown() {
   shutdown_ = true;
 
   // Cancel the outstanding jobs.
   for (JobMap::iterator it = jobs_.begin(); it != jobs_.end(); ++it)
     it->second->Cancel();
   jobs_.clear();
 }
@@ skipping 212 matching lines @@
          it != observers_.end(); ++it) {
       (*it)->OnCancelResolution(request_id, info);
     }
 
     net_log.EndEvent(NetLog::TYPE_HOST_RESOLVER_IMPL_OBSERVER_ONCANCEL);
   }
 
   net_log.EndEvent(NetLog::TYPE_HOST_RESOLVER_IMPL);
 }
 
-void HostResolverImpl::Flush() {
+void HostResolverImpl::OnIPAddressChanged() {
   if (cache_.get())
     cache_->clear();
   if (ipv6_probe_monitoring_) {
     DiscardIPv6ProbeJob();
     ipv6_probe_job_ = new IPv6ProbeJob(this);
     ipv6_probe_job_->Start();
   }
 }
 
 void HostResolverImpl::DiscardIPv6ProbeJob() {
@@ skipping 97 matching lines @@
     if (r == req)
       return error;
 
     r->OnComplete(error, AddressList());
   }
 
   return ERR_IO_PENDING;
 }
 
 }  // namespace net