QGraphicsWidgetPrivate::init had a special code path for setting
the item's parent. For some reason that code path caused the
ItemChildAddedChange notification not to be sent to the parent
element, which is wrong. Instead use the "normal" path, which is
what the QGraphicsItem constructor does anyhow.
Change-Id: Iad84cae05d797022a45977d35ca00c80c17c306a
Task-number: QTBUG-45867
Reviewed-by: Andreas Aardal Hanssen <andreas@hanssen.name>
3287e7a68a