GrTessellator: fix two NaN issues.

If a point in the path rounds to +inf/-inf, the intersection code can
produce NaN, which is unsortable. Fix: ignore non-finite intersections.

Quadratic interpolation can sometimes produce NaN, which will never
satisfy the flatness criterion. Abort if any of the interpolated points
are non-finite.

Bug:732023
Change-Id: If5881796e589c75b8f74459f42d00918619713a2
Reviewed-on: https://skia-review.googlesource.com/19467
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
2 files changed