Code review comment for lp:~nick-dedekind/qtmir/lp1475678.surface-occlude

One thing to look at is to what happens when MirSurfaceItem::setSurface() is called and the MirSurfaceItem in question is already hidden. You have to synce the visibility of MirSurface with the one of its MirSurfaceItem inside setSurface().

Another thing to consider is what happens when there are multiple MirSurfaceItems displaying the same MirSurface? It will only get occluded if *all* items showing it are hidden. In other words: the MirSurface will be exposed as long as there's some visible MirSurfaceItem in the scene displaying it.