Always use NonBlocking IO for UDP sockets on Windows.

net/socket/socket_test_util.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_SOCKET_SOCKET_TEST_UTIL_H_
 #define NET_SOCKET_SOCKET_TEST_UTIL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 762 matching lines @@
             int buf_len,
             const CompletionCallback& callback) override;
   int SetReceiveBufferSize(int32_t size) override;
   int SetSendBufferSize(int32_t size) override;
   int SetDoNotFragment() override;
 
   // DatagramSocket implementation.
   void Close() override;
   int GetPeerAddress(IPEndPoint* address) const override;
   int GetLocalAddress(IPEndPoint* address) const override;
-  void UseNonBlockingIO() override;
   const NetLogWithSource& NetLog() const override;
 
   // DatagramClientSocket implementation.
   int Connect(const IPEndPoint& address) override;
   int ConnectUsingNetwork(NetworkChangeNotifier::NetworkHandle network,
                           const IPEndPoint& address) override;
   int ConnectUsingDefaultNetwork(const IPEndPoint& address) override;
   NetworkChangeNotifier::NetworkHandle GetBoundNetwork() const override;
 
   // AsyncSocket implementation.
@@ skipping 253 matching lines @@
 
 // Helper function to get the total data size of the MockReads in |reads|.
 int64_t CountReadBytes(const MockRead reads[], size_t reads_size);
 
 // Helper function to get the total data size of the MockWrites in |writes|.
 int64_t CountWriteBytes(const MockWrite writes[], size_t writes_size);
 
 }  // namespace net
 
 #endif  // NET_SOCKET_SOCKET_TEST_UTIL_H_