Modify a temporary hack to be more inclusive....

net/base/host_resolver_impl.cc

 // Copyright (c) 2006-2008 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 <ws2tcpip.h>
 #include <wspiapi.h>  // Needed for Win2k compat.
 #elif defined(OS_POSIX)
 #include <netdb.h>
 #include <sys/socket.h>
 #endif
 #if defined(OS_LINUX)
 #include <resolv.h>
 #endif
 
 #include "base/compiler_specific.h"
+#include "base/debug_util.h"
 #include "base/message_loop.h"
 #include "base/stl_util-inl.h"
 #include "base/string_util.h"
 #include "base/time.h"
 #include "base/worker_pool.h"
 #include "net/base/address_list.h"
 #include "net/base/host_resolver_proc.h"
 #include "net/base/net_errors.h"
 
 #if defined(OS_WIN)
@@ skipping 331 matching lines @@
     job->Start();
   }
 
   // Completion happens during OnJobComplete(Job*).
   return ERR_IO_PENDING;
 }
 
 // See OnJobComplete(Job*) for why it is important not to clean out
 // cancelled requests from Job::requests_.
 void HostResolverImpl::CancelRequest(RequestHandle req_handle) {
+  if (shutdown_) {
+    // TODO(eroman): temp hack for: http://crbug.com/16972.
+    // Because we destroy outstanding requests during Shutdown() as part of
+    // hack http://crbug.com/15513, |req_handle| is already cancelled.
+    LOG(ERROR) << "Called HostResolverImpl::CancelRequest() after Shutdown().";
+    StackTrace().PrintBacktrace();
+    return;
+  }
   Request* req = reinterpret_cast<Request*>(req_handle);
   DCHECK(req);
   DCHECK(req->job());
   // NULL out the fields of req, to mark it as cancelled.
   req->MarkAsCancelled();
   NotifyObserversCancelRequest(req->id(), req->info());
 }
 
 void HostResolverImpl::AddObserver(Observer* observer) {
   observers_.push_back(observer);
@@ skipping 94 matching lines @@
 
 void HostResolverImpl::NotifyObserversCancelRequest(int request_id,
                                                 const RequestInfo& info) {
   for (ObserversList::iterator it = observers_.begin();
        it != observers_.end(); ++it) {
     (*it)->OnCancelResolution(request_id, info);
   }
 }
 
 }  // namespace net