Chromium, like Firefox, uses toolkits only for basic desktop bootstrapping and integration. This addition only concerns Linux, on which the current default for

Chromium, like Firefox, uses toolkits only for basic desktop bootstrapping and integration. This addition only concerns Linux, on which the current default for that is gtk3. The only user-visible effect of switching toolkit should be the "File choosing" dialogs, the non-default (ctrl+shift+p) print dialog, and maybe the non-default window decorations (if they are rendered client-side, i.e. on Wayland?).