[FaceRest] Improve type safety to call the setup done callback.

Passing an object of a sub class via a void pointer is haven for BUGs.

For example, when we use the following class,

class Sub : public Base {
 ...
} sub;

it is a little complecated to choose the appropriate pointer from
the candidates:
  &sub
  (void *)&sub
  (Base *)&sub
  static_cast<Base *>(&sub)
  reinterpret_cast<Base *>(&sub)
  reinterpret_cast<void *>(&sub)