Updated HWUI to calculate the stretch bounds for a surface

Added logic to StretchEffect to be able to calculate the
stretched position of a pixel on an input texture based
on the current stretch parameters.

Updated shader to leverage linear easing instead of
cubic in order to have a reversible method that
can be used to map input textures to the corresponding
stretch position.

Bug: 179047472
Test: manual

Change-Id: Id32afcf0df1cca03e68ac0c594d307a1090264f2