When an application has background processing enabled, for example for
communicating with an external accessory or getting location updates,
it might trigger code that does UI updates, which will kill the app as
doing UI in the background is not allowed on iOS.
We guard against this by propagating the backgrounding as updated expose
events with a non-exposed region and isExposed() returning false. This
means clients who correctly use QWindow::isExposed() to guard their
drawing code (including the scene-graph), will live to see another day.
Task-number: QTBUG-36956
Change-Id: Ib708394d33093affe68c9f2c7abde7e54be5ec74
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
a3634e4b2b