Quick3D Texture elements require some window signals to show QML item
as texture, so we fake them to make textures appear in form editor
and state preview. To prevent texture mirroring, flipV value
is force set at proxy creation. To keep state preview up to date,
we trigger multiple render passes if there are any QML items used
as texture sources in quick3D textures.
Task-number: QDS-2290
Change-Id: I16c34aad943213c0b737fdb073333be3bbd40f2d
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
