app-system: Add back StartupWMClass matching
While unfortunate that we still have to scan all apps with get_all(), support for this feature will be short-lived, so hopefully we can drop it in the future as new apps adapt to the desktop file / app ID recommendations. For now, simply scan all desktop IDs. https://bugzilla.gnome.org/show_bug.cgi?id=711631
parent
e10d2a68