The 'have_clip' variable has repeatedly confused me to meaning that
there is a clip. What it actually means is that the effective clip
covers the whole view; the 'redraw_clip == NULL' meaning full redraw is
an important implementation detail for the context, and makes the
intention of the variable unclear; especially since we will after a
couple of blocks will *always* have a clip, just that it covers the
whole view.
Rename the variable to 'is_full_redraw' and negate the meaning, aiming
to make things a lot more clear.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/1042
86ccc28413