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

net/udp/udp_socket_libevent.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/udp/udp_socket_libevent.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <netdb.h>
 #include <net/if.h>
@@ skipping 109 matching lines @@
   write_buf_ = NULL;
   write_buf_len_ = 0;
   write_callback_.Reset();
   send_to_address_.reset();
 
   bool ok = read_socket_watcher_.StopWatchingFileDescriptor();
   DCHECK(ok);
   ok = write_socket_watcher_.StopWatchingFileDescriptor();
   DCHECK(ok);
 
-  if (IGNORE_EINTR(close(socket_)) < 0)
+  if (IGNORE_EINTR(close(socket_)) < 0) {
     PLOG(ERROR) << "close";
 
+    // Crash if errno=EBADF, to debug crbug.com/452121 .

[mef, 2015/02/11 19:25:35]

Could you add TODO(sergeyu) to remove it once investigation is complete?

+    CHECK_NE(EBADF, errno);
+  }
+
   socket_ = kInvalidSocket;
   addr_family_ = 0;
   is_connected_ = false;
 }
 
 int UDPSocketLibevent::GetPeerAddress(IPEndPoint* address) const {
   DCHECK(CalledOnValidThread());
   DCHECK(address);
   if (!is_connected())
     return ERR_SOCKET_NOT_CONNECTED;
@@ skipping 606 matching lines @@
     return MapSystemError(errno);
 
   return OK;
 }
 
 void UDPSocketLibevent::DetachFromThread() {
   base::NonThreadSafe::DetachFromThread();
 }
 
 }  // namespace net