Always use NonBlocking IO for UDP sockets on Windows.

net/dns/address_sorter_posix_unittest.cc

 // 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.
 
 #include "net/dns/address_sorter_posix.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "net/base/ip_address.h"
@@ skipping 43 matching lines @@
   int GetPeerAddress(IPEndPoint* address) const override {
     NOTIMPLEMENTED();
     return OK;
   }
   int GetLocalAddress(IPEndPoint* address) const override {
     if (!connected_)
       return ERR_UNEXPECTED;
     *address = local_endpoint_;
     return OK;
   }
-  void UseNonBlockingIO() override {}
   int ConnectUsingNetwork(NetworkChangeNotifier::NetworkHandle network,
                           const IPEndPoint& address) override {
     NOTIMPLEMENTED();
     return ERR_NOT_IMPLEMENTED;
   }
   int ConnectUsingDefaultNetwork(const IPEndPoint& address) override {
     NOTIMPLEMENTED();
     return ERR_NOT_IMPLEMENTED;
   }
   NetworkChangeNotifier::NetworkHandle GetBoundNetwork() const override {
@@ skipping 254 matching lines @@
   AddMapping("4000::1", "4000::10");  // global unicast
   AddMapping("ff32::2", "fe81::20");  // deprecated link-local multicast
   GetSourceInfo("fe81::20")->deprecated = true;
   const char* const addresses[] = { "ff3e::1", "ff32::2", "4000::1", "ff32::1",
                                     "::1", "8.0.0.1", NULL };
   const int order[] = { 4, 3, 0, 2, 1, -1 };
   Verify(addresses, order);
 }
 
 }  // namespace net