Revert "Fixed incorrect calculation of dirty invalidation area"

bug:11351836

Because SeekBar's thumb Drawable (among others) is positioned without
padding offset baked in, include that offset when invalidating.

This revert fixes invalidate positioning in the system volume SeekBar,
where the original CL broke full redrawing of the thumb Drawable when
it switched states.

This reverts commit e9018f77.

Change-Id: I5b3b07e47f466269f8d349e9a63dc29bf213120b