tiny concave path point fix

The tiny path added to PathTest.cpp has
tinier cross products (e.g. 1e-12)
so appears to be a series of unbending
lines as far as getConvexity is concerned.

This point fix looks for paths that
do not bend left or right or go backwards,
but do have a bounds, and calls them
concave.

A better fix may be to consider empty
and degenerate paths to be concave
instead of convex; I don't know if
anyone relies on the existing behavior.

Another better fix may be to change
the math to compute the path turns
even though the numbers are very small;
on the surface, very difficult.

R=bsalomon@google.com,reed@google.com
Bug:755839
Change-Id: Ie2280f3f0b95fecab2899f5fc579fd39258e0647
Reviewed-on: https://skia-review.googlesource.com/38720
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Cary Clark <caryclark@google.com>
2 files changed