Add a dedicated error code for TLS 1.3 interference.

net/log/net_log_event_type_list.h

Index: net/log/net_log_event_type_list.h
diff --git a/net/log/net_log_event_type_list.h b/net/log/net_log_event_type_list.h
index c73eefada38f684a351c38adc0c020272430da15..1981ab5ac3947e33559211c98dcd767b25894ee4 100644
--- a/net/log/net_log_event_type_list.h
+++ b/net/log/net_log_event_type_list.h
@@ -563,6 +563,15 @@ EVENT_TYPE(SSL_VERSION_FALLBACK)
 //   }
 EVENT_TYPE(SSL_CIPHER_FALLBACK)
 
+// An SSL connection needs to be retried with a lower protocol version to detect
+// if the error was due to a middlebox interfering with the protocol version we
+// offered.
+// The following parameters are attached to the event:
+//   {
+//     "net_error": <Net integer error code which triggered the probe>,
+//   }
+EVENT_TYPE(SSL_VERSION_INTERFERENCE_PROBE)
+
 // We found that our prediction of the server's certificates was correct and
 // we merged the verification with the SSLHostInfo. (Note: now obsolete.)
 EVENT_TYPE(SSL_VERIFICATION_MERGED)