Always use NonBlocking IO for UDP sockets on Windows.

net/socket/udp_client_socket.cc

 // Copyright (c) 2011 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/socket/udp_client_socket.h"
 
 #include "net/base/net_errors.h"
 
 namespace net {
 
@@ skipping 98 matching lines @@
 }
 
 int UDPClientSocket::SetDoNotFragment() {
   return socket_.SetDoNotFragment();
 }
 
 const NetLogWithSource& UDPClientSocket::NetLog() const {
   return socket_.NetLog();
 }
 
-void UDPClientSocket::UseNonBlockingIO() {
-#if defined(OS_WIN)
-  socket_.UseNonBlockingIO();
-#endif
-}
-
 }  // namespace net