When instantiating static plugins no check is done whether the
QQmlExtensionInterface is declared. Therefore all user plugins are
instantiated in the Qml thread, which may cause problems.
Task-number: QTBUG-52012
Change-Id: Ia91ec5ec7b2a9721bd11e3648cdc161855b4454e
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>
Sebastian Lösch