Implement getTransparentRegion() using SkLatticeIter

This allows us to delete utils/NinePatchImpl.cpp and
utils/NinePatch.h

Test: Passed cts tests - DrawableTest, NinePatchTest,
NinePatchDrawableTest.

Change-Id: I6b5d09fa3479e758d8b931fa0e977c25f4435a7c
8 files changed