The QWidget overload of qWaitForWindowExposed waits for the widget's
top level QWindow, which for the viewport is the graphics-view.
We want to explicitly wait for the viewport to be exposed, as the
viewport is covering the whole graphics-view, preventing it from
being exposed. See a6991376c.
Change-Id: I86df43871126562f09e4ce14931bc6fc7f06263d
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
64bce9bbff