When receiving OOB data on a socket, return ERR_OOB_DATA.

net/socket/socket_libevent.cc

 // Copyright 2014 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/socket_libevent.h"
 
 #include <errno.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
 
@@ skipping 400 matching lines @@
     return;
 
   bool ok = write_socket_watcher_.StopWatchingFileDescriptor();
   DCHECK(ok);
   waiting_connect_ = false;
   base::ResetAndReturn(&write_callback_).Run(rv);
 }
 
 int SocketLibevent::DoRead(IOBuffer* buf, int buf_len) {
   int rv = HANDLE_EINTR(read(socket_fd_, buf->data(), buf_len));
-  return rv >= 0 ? rv : MapSystemError(errno);
+  if (rv >= 0) {
+    return rv;
+  } else if (errno != EAGAIN) {
+    return MapSystemError(errno);
+  }
+
+  // The socket may have OOB data waiting, and libevent does not distinguish
+  // between ready inline and out-of-band data when it activates the
+  // callback. See if there is OOB data available.
+  rv = HANDLE_EINTR(recv(socket_fd_, buf->data(), buf_len, MSG_OOB));
+  if (rv >= 0) {
+    return ERR_OOB_DATA;
+  }
+  return ERR_IO_PENDING;
 }
 
 void SocketLibevent::ReadCompleted() {
   int rv = DoRead(read_buf_.get(), read_buf_len_);
   if (rv == ERR_IO_PENDING)
     return;
 
   bool ok = read_socket_watcher_.StopWatchingFileDescriptor();
   DCHECK(ok);
   read_buf_ = NULL;
@@ skipping 41 matching lines @@
     write_buf_ = NULL;
     write_buf_len_ = 0;
     write_callback_.Reset();
   }
 
   waiting_connect_ = false;
   peer_address_.reset();
 }
 
 }  // namespace net