The current preference API - buildPrefsWidget() - predates client-side
decorations. While extension authors have been finding ways around
the limitation of not having access to the window/titlebar, the change
to the new Adwaita API seems like a good time for an updated API that
officially provides that access (as far as allowed by libadwaita).
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2012>
Adapt the new GNOME platform API for the upcoming 42. This makes
sure that we get the latest version of the stylesheet, as well as
support for the new dark mode.
Using the dedicated preference API also gives extensions with more
complex preferences an easier and standardized way for implementing
multi-page preferences.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2012>
The error UI comprises the bits that are actually custom. Splitting them
out from the off-the-shelf window makes it easier to replace the dialog
with libadwaita's dedicated preference window.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2012>
