[NetworkChangeNotifier] Run Windows connection type computation on other thread

net/base/network_change_notifier.h

 // Copyright (c) 2012 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_H_
 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 340 matching lines @@
   // will be successfully.
   static bool IsOffline();
 
   // Returns true if |type| is a cellular connection.
   // Returns false if |type| is CONNECTION_UNKNOWN, and thus, depending on the
   // implementation of GetConnectionType(), it is possible that
   // IsConnectionCellular(GetConnectionType()) returns false even if the
   // 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
   // interfaces if they have the same interface type.
   static ConnectionType ConnectionTypeFromInterfaceList(
       const NetworkInterfaceList& interfaces);
 
   // Like Create(), but for use in tests.  The mock object doesn't monitor any
   // events, it merely rebroadcasts notifications when requested.
   static NetworkChangeNotifier* CreateMock();
@@ skipping 160 matching lines @@
                                                   ConnectionType type);
   static void NotifyObserversOfSpecificNetworkChange(NetworkChangeType type,
                                                      NetworkHandle network);
 
   // Stores |config| in NetworkState and notifies OnDNSChanged observers.
   static void SetDnsConfig(const DnsConfig& config);
   // Stores |config| in NetworkState and notifies OnInitialDNSConfigRead
   // 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;
   friend class NetworkChangeNotifierLinuxTest;
   friend class NetworkChangeNotifierWinTest;
 
   class NetworkState;
   class NetworkChangeCalculator;
 
   void NotifyObserversOfIPAddressChangeImpl();
@@ skipping 30 matching lines @@
 
   // Set true to disable non-test notifications (to prevent flakes in tests).
   static bool test_notifications_only_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifier);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_CHANGE_NOTIFIER_H_