bug#33294: xwidget-insert crashes Emacs

[Eli Zaretskii]

> From: Evgeny Zajcev <lg.zevlg@gmail.com>
> Date: Wed, 7 Nov 2018 00:13:20 +0300
> 
> Emacs from git crashes on next code:
> 
>   (require 'xwidget)
>   (with-temp-buffer
>     (xwidget-insert (point-min) 'webkit (buffer-name) 320 240))

Thank you for your report.  Please show a GDB backtrace from the
crash.

> I know about at least one character required to attach text property to it, 
> however I think elisp code should not
> crash the Emacs

Right.