You don't need TGame part to inform TRenderer. What you do is that both TGame and TRenderner have acces to same data (gamemap, units position, etc).
So whenever TRenderer is doing a rendering pass you actually inform TGame part so that it doesn't process any game related data until renderning pass is compleete. This is to avoid corrupted graphics (graphics rendered from two different ingame states). Also this avoids any Acces Violation that may arise when two parts of your application try to acces the same data.