Add CHECK() in UdpSocketLibevent to debug crbug.com/452121

net/udp/udp_socket_win.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_UDP_UDP_SOCKET_WIN_H_
 #define NET_UDP_UDP_SOCKET_WIN_H_
 
 #include <qos2.h>
 #include <winsock2.h>
 
@@ skipping 32 matching lines @@
   // Returns a net error code.
   int Connect(const IPEndPoint& address);
 
   // Binds the address/port for this socket to |address|.  This is generally
   // only used on a server. Should be called after Open().
   // Returns a net error code.
   int Bind(const IPEndPoint& address);
 
   // Closes the socket.
   // TODO(rvargas, hidehiko): Disallow re-Open() after Close().
-  void Close();
+  int Close();
 
   // Copies the remote udp address into |address| and returns a net error code.
   int GetPeerAddress(IPEndPoint* address) const;
 
   // Copies the local udp address into |address| and returns a net error code.
   // (similar to getsockname)
   int GetLocalAddress(IPEndPoint* address) const;
 
   // IO:
   // Multiple outstanding read requests are not supported.
@@ skipping 297 matching lines @@
   SetFlowFn set_flow_func_;
 
   FRIEND_TEST_ALL_PREFIXES(UDPSocketTest, SetDSCPFake);
   DISALLOW_COPY_AND_ASSIGN(QwaveAPI);
 };
 
 
 }  // namespace net
 
 #endif  // NET_UDP_UDP_SOCKET_WIN_H_