Fix bug #11537133 Hideycling looks broken (KOT36), missing left padding

- enforce the Drawable boolean getPadding(Rect) contract for NinePatchDrawable
and DrawableContainer.

- as NinePatchDrawable was not enforcing it, the consequence was that the
mUserPaddingLeftInitial / mUserPaddingRitghInitial were reset to "0" (even
if they got the correct value before the reset).

Change-Id: I1efe7fad5f89c0ca47f90189f6d89940e0e9c6ae