xdg-foreign: clean up
This commit removes extra wlr_xdg_toplevel_set_parent() calls, simplifies wlr_surface->wlr_xdg_toplevel conversion logic, makes related structures store wlr_xdg_toplevel objects directly instead of wlr_surface objects, and improves the code style.
Breaking changes
-
wlr_xdg_foreign_{exported,imported_child_v{1,2}}.surface
fields have been replaced withstruct wlr_xdg_toplevel *toplevel
.