bug:16140822
bug:16566746
This allows background drawables to alter the opacity of a shadow
being cast with their own alpha values.
Change-Id: I49698cc7c1bf4b2b55ffe2f82899543ca62bc61c
bug:16142564
Additionally, better define behavior around null outline providers:
A view with an empty outline, and setClipToOutline=true will not be
rendered, though one with a null outline provider
(and thus no outline) will be.
Change-Id: Ic9549841b107b2eb51b417c66058a0cd69dd89eb