display segfaults in cc_display_config_set_minimum_size when used outside of GNOME
The issue has some Ubuntu report, e.g https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/1870735
Starting g-c-c -> display under a non GNOME session leads to a segfault, ideally the code would just display a default empty page rather than segfaulting
#0 cc_display_config_set_minimum_size (self=0x0, width=740, height=530) at ../panels/display/cc-display-config.h:139
No locals.
#1 0x000055619766ae11 in reset_current_config (panel=0x5561990dc520) at ../panels/display/cc-display-panel.c:882
current = 0x0
old = 0x0
outputs = <optimized out>
l = <optimized out>
#2 0x000055619766bee1 in on_screen_changed (panel=0x5561990dc520) at ../panels/display/cc-display-panel.c:918
No locals.
#3 0x00007f6e432136e2 in g_closure_invoke () from /srv/daisy.ubuntu.com/production/cache/Ubuntu 19.10/cache-acdK_c/sandbox/Ubuntu 19.10/amd64/report-sandbox/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
No symbol table info available.
#4 0x00007f6e43227544 in signal_emit_unlocked_R () from /srv/daisy.ubuntu.com/production/cache/Ubuntu 19.10/cache-acdK_c/sandbox/Ubuntu 19.10/amd64/report-sandbox/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
No symbol table info available.
#5 0x00007f6e43230327 in g_signal_emit_valist () from /srv/daisy.ubuntu.com/production/cache/Ubuntu 19.10/cache-acdK_c/sandbox/Ubuntu 19.10/amd64/report-sandbox/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
No symbol table info available.
#6 0x00007f6e432309b3 in g_signal_emit () from /srv/daisy.ubuntu.com/production/cache/Ubuntu 19.10/cache-acdK_c/sandbox/Ubuntu 19.10/amd64/report-sandbox/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
No symbol table info available.
#7 0x00005561976704a3 in _cc_display_config_manager_emit_changed (self=<optimized out>) at ../panels/display/cc-display-config-manager.c:54
No locals.
#8 0x00005561976701f7 in got_current_state (object=0x556198fa8670, result=0x556199a1a580, data=data@entry=0x556199ac3e40) at ../panels/display/cc-display-config-manager.h:29
self = <optimized out>
variant = <optimized out>
error = 0x556199aa8d30