Always use NonBlocking IO for UDP sockets on Windows.

net/socket/fuzzed_datagram_client_socket.h

 // Copyright 2016 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_FUZZED_DATAGRAM_CLIENT_SOCKET_H_
 #define NET_SOCKET_FUZZED_DATAGRAM_CLIENT_SOCKET_H_
 
 #include "net/socket/datagram_client_socket.h"
 
 #include <stdint.h>
@@ skipping 25 matching lines @@
   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;
 
   // 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;
 
   // Socket implementation:
   int Read(IOBuffer* buf,
            int buf_len,
            const CompletionCallback& callback) override;
   int Write(IOBuffer* buf,
             int buf_len,
             const CompletionCallback& callback) override;
   int SetReceiveBufferSize(int32_t size) override;
@@ skipping 15 matching lines @@
   IPEndPoint remote_address_;
 
   base::WeakPtrFactory<FuzzedDatagramClientSocket> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FuzzedDatagramClientSocket);
 };
 
 }  // namespace net
 
 #endif  // NET_SOCKET_FUZZED_DATAGRAM_CLIENT_SOCKET_H_