macOS: Ensure all windows are created on a valid screen

We rely on AppKit repositioning the window if the original position
is not on any of the available screens. We do this by keeping the
original position, but using the primary screen as reference.

This doesn't work unless the window has a title bar, so in the corner
case where the window has an invalid position, we apply the title bar
style mask for a brief moment, so that AppKit will place the window
correctly.

Task-number: QTBUG-69221
Change-Id: If66cac36bf36f051570ba5854951ce4504fe771f
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

0 files changed, 0 insertions, 0 deletions