hg: openjfx/jfx-dev/rt: 8226537: Multi-level Stage::initOwner can crash gnome-shell or X.org server

[kevin.rushforth at oracle.com]

Changeset: 02b278ddb815
Author:    kcr
Date:      2019-06-28 09:05 -0700
URL:       http://hg.openjdk.java.net/openjfx/jfx-dev/rt/rev/02b278ddb815

8226537: Multi-level Stage::initOwner can crash gnome-shell or X.org server
Reviewed-by: kcr, pbansal

! modules/javafx.graphics/src/main/native-glass/gtk/glass_window.cpp