[NetworkChangeNotifier] Run Windows connection type computation on other thread

net/base/network_change_notifier.h

Index: net/base/network_change_notifier.h
diff --git a/net/base/network_change_notifier.h b/net/base/network_change_notifier.h
index 66789794c0535c8456e74a016f9858d48aae8937..687499fd03dd60c92566e72b65e92c4279a5d8e7 100644
--- a/net/base/network_change_notifier.h
+++ b/net/base/network_change_notifier.h
@@ -358,6 +358,10 @@ class NET_EXPORT NetworkChangeNotifier {
   // current connection is cellular.
   static bool IsConnectionCellular(ConnectionType type);
 
+  // Infer connection type from |GetNetworkList|. If all network interfaces
+  // have the same type, return it, otherwise return CONNECTION_UNKNOWN.
+  static ConnectionType ConnectionTypeFromInterfaces();

[pauljensen, 2017/05/22 18:01:51]

Can we move this protected again?  You can make RecomputeCurrentConnectionType()
a NCNWin static member.

[jkarlin, 2017/05/23 11:44:38]

Done.

+
   // Gets the current connection type based on |interfaces|. Returns
   // CONNECTION_NONE if there are no interfaces, CONNECTION_UNKNOWN if two
   // interfaces have different connection types or the connection type of all
@@ -538,10 +542,6 @@ class NET_EXPORT NetworkChangeNotifier {
   // observers.
   static void SetInitialDnsConfig(const DnsConfig& config);
 
-  // Infer connection type from |GetNetworkList|. If all network interfaces
-  // have the same type, return it, otherwise return CONNECTION_UNKNOWN.
-  static ConnectionType ConnectionTypeFromInterfaces();
-
  private:
   friend class HostResolverImplDnsTest;
   friend class NetworkChangeNotifierAndroidTest;