A foreign window can be used both for embedding a Qt window into a
native window hierarchy, or for embedding a native window into a Qt
window hierarchy. In the former case, we should not modify the foreign
window in any way. Since the platform does not know anything about the
intended use case at the time of the foreign window creation, it should
avoid modifying the foreign window in any way, and should instead pick
up the foreign window state and reflect that through QWindow.
Pick-to: 6.5
Change-Id: Id2e39d101277ecebd656d615cea3e7f734a4b0a6
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
