Handle degenerate 2pt conical center values gracefully

SkMatrix::setPolyToPoly() may fail to map degenerate values.  Handle
this case explicitly, instead of assuming it never fails.

BUG=chromium:738746
TBR=

Change-Id: Ie1049b98f7e07ae5d6bdb706ba7b4a399388e5d8
Reviewed-on: https://skia-review.googlesource.com/21375
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed