Chromium starts with a black window.

Log shows:

[1706483:1706483:1006/210913.766487:ERROR:content/app/content_main_runner_impl.cc:456] Failed to initialize cpuinfo
[1:1:1006/210913.774545:ERROR:content/app/content_main_runner_impl.cc:456] Failed to initialize cpuinfo
[1706463:1706463:1006/210914.068351:ERROR:content/browser/browser_main_loop.cc:286] GLib-GObject: g_object_set_is_valid_property: object class 'GtkSettings' has no property named 'gtk-modules'
../../sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.cc:**CRASHING**:seccomp-bpf failure in syscall nr=0xdf arg1=0xffffffffffffffda arg2=0x20 arg3=0x2cc400074770 arg4=0x20

(process:1706463): Gtk-WARNING **: 21:09:14.541: Use GtkSettings:gtk-interface-color-scheme instead
[1706463:1706463:1006/210914.722711:ERROR:components/dbus/xdg/request.cc:173] Request ended (non-user cancelled).


Reproducible: Always

Steps to Reproduce:
1. Just run `chromium-browser`
Actual Results:
A black chromium window

Expected Results:
Normal window with all elements of a web browser

Additional Information:
If I add `--disable-seccomp-filter-sandbox` to `CHROMIUM_USER_FLAGS` var in `/etc/chromium/chromium.conf`, the browser would start normally.