[net/dns] Isolate DnsConfigWatcher from DnsConfigService.

net/base/network_change_notifier_win.h

Index: net/base/network_change_notifier_win.h
diff --git a/net/base/network_change_notifier_win.h b/net/base/network_change_notifier_win.h
index aee5304ff6fe3d03506fa9827f99f55a1b16c14b..4322e88eb7fc882c541ad5650d530fc0ab2ba12b 100644
--- a/net/base/network_change_notifier_win.h
+++ b/net/base/network_change_notifier_win.h
@@ -10,6 +10,7 @@
 
 #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"
@@ -47,6 +48,7 @@ class NET_EXPORT_PRIVATE NetworkChangeNotifierWin
   int sequential_failures() { return sequential_failures_; }
 
  private:
+  class DnsWatcherThread;
   friend class NetworkChangeNotifierWinTest;
 
   // NetworkChangeNotifier methods:
@@ -89,6 +91,9 @@ class NET_EXPORT_PRIVATE NetworkChangeNotifierWin
   // 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);
 };