The clientRect might be empty when creating a window of zero size. The
side effect of a division by zero is that matrix transformation fails
and hence the swapchain gets into an invalid state.
Change-Id: Idbaed72deadb7b87052ac27e194a40d1810e6f7a
Reviewed-by: Andrew Knight <andrew.knight@intopalo.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>