These member functions take logic units, and the only case when omitting
PixelToLogic() all the time works is when both the widget itself and
render context has a pixel map unit.

Add missing PixelToLogic() calls where the input is in pixels, so in
case the render context has some logic units, the output is still
painted at the correct location.

This is needed for e.g. tiled rendering of the scrollbar of Writer
comment widgets.

Change-Id: Ideb75625b1f6349c5f18342e6f438fd5d7c31dcd
(cherry picked from commit f2081039)