The lighting direction in the feLighting sample of effect-reference-hw has a y-flip. Not sure yet if this is a Skia or WebKit bug.
Theory: the GrTextures created by wrapping the compositor's platform textures do not have their origin set correctly (TopLeft vs BottomLeft).
Committed r142018: <http://trac.webkit.org/changeset/142018>
Committed r142291: <http://trac.webkit.org/changeset/142291>