The boundingRect represents the clip rectangle of an item rather than
the size and position of its unclipped content.  This would prevent any
content from being clipped except the boundingRect is only re-evaluated
when the size of the item changes so the content is instead clipped to
the size of the original content.

Task-number: QTBUG-23422
Change-Id: I96f830f833129b3230f65452db67b00028c40d6a
Reviewed-by: Martin Jones <martin.jones@nokia.com>