Clean up dns prefetch code, and also port it.

chrome/browser/browser_process_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 "chrome/browser/browser_process_impl.h"
 
 #include "base/command_line.h"
 #include "base/path_service.h"
 #include "base/thread.h"
 #include "base/waitable_event.h"
 #include "chrome/browser/browser_trial.h"
 #include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/debugger/debugger_wrapper.h"
 #include "chrome/browser/google_url_tracker.h"
 #include "chrome/browser/metrics/metrics_service.h"
+#include "chrome/browser/net/dns_global.h"
 #include "chrome/browser/profile_manager.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/renderer_host/resource_dispatcher_host.h"
 #include "chrome/browser/safe_browsing/safe_browsing_service.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/l10n_util.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/pref_service.h"
@@ skipping 141 matching lines @@
   if (resource_dispatcher_host_.get()) {
     // Need to tell Safe Browsing Service that the IO thread is going away
     // since it cached a pointer to it.
     if (resource_dispatcher_host()->safe_browsing_service())
       resource_dispatcher_host()->safe_browsing_service()->ShutDown();
 
     // Cancel pending requests and prevent new requests.
     resource_dispatcher_host()->Shutdown();
   }
 
+  // Shutdown DNS prefetching now to ensure that network stack objects
+  // living on the IO thread get destroyed before the IO thread goes away.
+  io_thread_->message_loop()->PostTask(FROM_HERE,
+      NewRunnableFunction(chrome_browser_net::ShutdownDnsPrefetch));
+
   // Need to stop io_thread_ before resource_dispatcher_host_, since
   // io_thread_ may still deref ResourceDispatcherHost and handle resource
   // request before going away.
   io_thread_.reset();
 
   // Clean up state that lives on the file_thread_ before it goes away.
   if (resource_dispatcher_host_.get()) {
     resource_dispatcher_host()->download_file_manager()->Shutdown();
     resource_dispatcher_host()->save_file_manager()->Shutdown();
   }
@@ skipping 193 matching lines @@
   // TODO(port): remove this completely, it has no business being here.
 #endif
 }
 
 void BrowserProcessImpl::CreateGoogleURLTracker() {
   DCHECK(google_url_tracker_.get() == NULL);
   scoped_ptr<GoogleURLTracker> google_url_tracker(new GoogleURLTracker);
   google_url_tracker_.swap(google_url_tracker);
 }