Make setter methods on Outline call setEmpty() based on params

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
5 files changed