Add AsWinding to convert SkPath with even odd fill to winding fill.
This basic implementation works for simple non-intersecting paths.
It may fail if contours in paths touch, specifically when the leftmost
point in a contour is shared with another contour.
The incomplete parts are marked with TODO in the code.
If this interface and implementation look promising, I will continue to
tackle the more difficult cases.
R=reed@google.com,bungeman@google.com
Bug: skia:7682
Change-Id: I479fba60072eb1391b451fcb819504245da2e2a9
Reviewed-on: https://skia-review.googlesource.com/147044
Commit-Queue: Cary Clark <caryclark@google.com>
Reviewed-by: Mike Reed <reed@google.com>
