Switch to the new WorkspaceLayout layout manager to allocate the window
clones of the overview properly using Clutters layouting mechanisms.
Since we now no longer make use of the fullGeometry, we can remove the
setFullGeometry() function from the Workspace class. Also we can stop
setting the actualGeometry on the Workspaces and WorkspaceViews and
instead just set the fixed position and size of the views to their
full or actual geometry. This also has the benefit that we no longer
have to set a custom clip, but can simply enable clip_to_allocation.
The geometry needs to be set inside a BEFORE_REDRAW later because
_updateWorkspacesActualGeometry() is called from a notify::allocation
handler.
This isn't doing any animations when showing/hiding the overview yet,
we'll add that in the next commit.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1305
Using CSS to center the title actor on the border is a bit ugly, because
it requires the CSS to match the calculations used in chromeHeights().
Also it is not possible to use CSS margins for cases where the position
of the actor is determined at run time, such as for the close button.
Instead use an invisible actor that spans between the horizontal and
vertical center lines of the border as guide when aligning the title
actor.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1313
Start using the new overlays we introduced in the last commit and remove
the WindowOverlay class and the objects for keeping track of them in the
Workspace.
The new layout which doesn't use the -shell-close-overlap CSS property
anymore sligthly changes the position of the close button to be a bit
further away from the actual window.
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1298
