QAbstractProxyModel::itemData/setItemData should behave
just like data()/setData() instead of calling the
QAbstractItemModel implementation.
Before this change the QAbstractProxyModel implementation
calls its the QAbstractItemModel implementation,
which ends up calling data()/setData() in a loop
bypassing the convenience of itemData/setItemData.
[ChangeLog][QtCore][QAbstractProxyModel] The itemData()
and setItemData() functions will now call the respective
implementations in the source model (after mapping the
index to a source index), matching what data() and
setData() already did.
Before, the proxy model simply called the default
implementations of itemData()/setItemData() in its own
base class (QAbstractItemModel).
Change-Id: I9e680d355f44fa130660dd7e1c8ac37484c1566e
Reviewed-by: David Faure <david.faure@kdab.com>
c27d2a57a4