check path bounds before trying to shadow

Bug: oss-fuzz:8331
Change-Id: Idbff0deb0b9968edf4b4fafd4cf497bbb71c64fa
Reviewed-on: https://skia-review.googlesource.com/128550
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Mike Reed <reed@google.com>
1 file changed