It appears the backport has already been done upstream. Both the missing commits are already in the gnome-3-28 branch of mutter, scheduled for inclusion in mutter version 3.28.4 (whenever that may be).
I have also verified that mutter version 3.28.3 fails, and the gnome-3-28 branch (721de281) works (with Nvidia driver 410).
This all means we should now wait for an official tag 3.28.4 from upstream and get that into bionic eventually.
It appears the backport has already been done upstream. Both the missing commits are already in the gnome-3-28 branch of mutter, scheduled for inclusion in mutter version 3.28.4 (whenever that may be).
I have also verified that mutter version 3.28.3 fails, and the gnome-3-28 branch (721de281) works (with Nvidia driver 410).
This all means we should now wait for an official tag 3.28.4 from upstream and get that into bionic eventually.