Don't overflow comparing index to size
Don't overflow comparing index to size

Bug: oss-fuzz:50408
Change-Id: Ifc0946a557b6c58cca7510974f339997c68d1447
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/572276
Reviewed-by: Robert Phillips <95e8ac5504948c7bf91b22c16a8dbb7ae7c66bfd@google.com>
Auto-Submit: Michael Ludwig <cb1f3dd24de0f0b611b26bc28bec758a551d9b7d@google.com>
Commit-Queue: Robert Phillips <95e8ac5504948c7bf91b22c16a8dbb7ae7c66bfd@google.com>

google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia