Fix crash when all the items in a QListView are hidden

Calling QIconModeViewBase::initDynamicLayout() on the second and
successive segments would return QPoint(-1,-1), resulting in a
totally empty area rectangle for all the items while in
QIconModeViewBase::doDynamicLayout(). This rectangle is used to
initialize the BSP tree, and produces an arithmetic exception when
empty.

Furthermore, a rendering bug was also apparent when displaying the
first item of a segment while the last item of the previous segment
was hidden.

Auto-tests included.

Reviewed-by: Olivier
Task-number: QTBUG-12308
(cherry picked from commit 3c7e7992461b1fef37ada68244f1b5b891015bda)

Conflicts:

	src/gui/itemviews/qlistview.cpp
	tests/auto/qlistview/tst_qlistview.cpp

0 files changed, 0 insertions, 0 deletions