When receiving OOB data on a socket, return ERR_OOB_DATA.

net/socket/socket_libevent.cc

Index: net/socket/socket_libevent.cc
diff --git a/net/socket/socket_libevent.cc b/net/socket/socket_libevent.cc
index 5f16c929ab202fd4c61ba4ed5070cb523fb0353d..001b8fb6f3595fc9e05415ad2aedb10f4486a3bf 100644
--- a/net/socket/socket_libevent.cc
+++ b/net/socket/socket_libevent.cc
@@ -418,7 +418,20 @@ void SocketLibevent::ConnectCompleted() {
 
 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() {