Implement coverage AA for skewed rects with local coords

Adds a path fallback for rects with local coords that can't be drawn
with an analytic shader. This is accomplished by modifying the view
matrix and then drawing the local rect/quad.

BUG=skia:5500, 7508
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2183223002

Review-Url: https://codereview.chromium.org/2183223002
1 file changed