Address fuzzer issue

Bug: skia:8261
Change-Id: I507e39b0d7ae4f0237153713679b46c1645922c1
Reviewed-on: https://skia-review.googlesource.com/148381
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
3 files changed