Disallow negative radii in deserialized SkRRects

bug= chromium:787124

Change-Id: I232ccd6bdfc2c176f97b97e24eabad6a9ce8e5e2
Reviewed-on: https://skia-review.googlesource.com/73901
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
2 files changed