Code review comment for lp:~andreas-pokorny/mir/compose-sequences-in-xkb-keymapper

+ xkb_keysym_t update_state(uint32_t scan_code, MirKeyboardAction direction, ComposeState* compose_state);
in light of
+ update_state(to_xkb_scan_code(scan_code), mir_keyboard_action_down, nullptr);

I think mir::optional_value<ComposeState*> as the new parameter makes sense. (or having two functions with different parameters).

not too bothered by that though, lgtm