Code review comment for lp:~alan-griffiths/miral/WindowControllerInterface-isVisible

> Is a state getter/interpreter something that belongs in the Controller?
> How do we know if the value returned by this changes?
>
> + const bool visible = m_controller && m_controller->isVisible(m_window);
> there should always be a controller in MirSurface, no need to check for its
> validity.

The tests segfault without the check. But if you want I can do some rework there.