What we are doing for now is setting ExternalContentsInPass always.
This way vulkanunderqml works as expected. For applications that do
not integrate external rendering this means that there is now an
additional secondary command buffer per render pass, but we can
live with this for now.
Later (Qt 6) there should be a way to declare this (that the application
will want to issue native rendering stuff) up front in QQuickWindow or
somewhere.
Change-Id: I736741f9b0eee2f8295b046bacdce862e6a546f5
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
ee702d9436