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

net/udp/udp_socket_libevent.cc

Index: net/udp/udp_socket_libevent.cc
diff --git a/net/udp/udp_socket_libevent.cc b/net/udp/udp_socket_libevent.cc
index 8dd102a8a77a47e9e71e8bd1b01c271bded104a7..8b494a117baa48b9570a4dc207317bf912af3ee7 100644
--- a/net/udp/udp_socket_libevent.cc
+++ b/net/udp/udp_socket_libevent.cc
@@ -127,9 +127,13 @@ void UDPSocketLibevent::Close() {
   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;