Windows QPA: Detect a SetParent into a native window and set isEmbedded

Detecting that a Qt window has been reparented into a native window and
setting isEmbedded automatically. While there is no specific message for
the change in the parent window, a WM_WINDOWPOSCHANGING message
indicating a change in the Z order is sent. We can recognize an
embedding condition by detecting that our QWindow does not have another
QWindow as a parent, but the HWND associated with it has another HWND as
a parent, which is not the desktop window.

This change should cover the use case where a Qt-based plugin must
return a HWND to a host application, where the host application will
then reparent the HWND as it sees fit, outside of Qt control.

Task-number: QTBUG-64116
Change-Id: Iec417c0dd55ad68eff1ea75bb6f5b5495489c31e
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

0 files changed, 0 insertions, 0 deletions