[net/dns] Isolate DnsConfigWatcher from DnsConfigService.

net/base/network_change_notifier_win.h

 // Copyright (c) 2011 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.
 
 #ifndef NET_BASE_NETWORK_CHANGE_NOTIFIER_WIN_H_
 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_WIN_H_
 #pragma once
 
 #include <windows.h>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/timer.h"
 #include "base/win/object_watcher.h"
 #include "net/base/net_export.h"
 #include "net/base/network_change_notifier.h"
 
 namespace net {
 
 // NetworkChangeNotifierWin inherits from NonThreadSafe, as all its internal
@@ skipping 17 matching lines @@
 
  protected:
   virtual ~NetworkChangeNotifierWin();
 
   // For unit tests only.
   bool is_watching() { return is_watching_; }
   void set_is_watching(bool is_watching) { is_watching_ = is_watching; }
   int sequential_failures() { return sequential_failures_; }
 
  private:
+  class DnsWatcherThread;
   friend class NetworkChangeNotifierWinTest;
 
   // NetworkChangeNotifier methods:
   virtual bool IsCurrentlyOffline() const OVERRIDE;
 
   // ObjectWatcher::Delegate methods:
   // Must only be called on the thread |this| was created on.
   virtual void OnObjectSignaled(HANDLE object) OVERRIDE;
 
   // Notifies IP address change observers of a change immediately, and notifies
@@ skipping 22 matching lines @@
   OVERLAPPED addr_overlapped_;
 
   base::OneShotTimer<NetworkChangeNotifierWin> timer_;
 
   // Number of times WatchForAddressChange has failed in a row.
   int sequential_failures_;
 
   // Used for calling WatchForAddressChange again on failure.
   base::WeakPtrFactory<NetworkChangeNotifierWin> weak_factory_;
 
+  // Thread on which we can run DnsConfigWatcher.
+  scoped_ptr<DnsWatcherThread> dns_watcher_thread_;
+
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifierWin);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_CHANGE_NOTIFIER_WIN_H_