More checks in ReflexHash setup

Bug: skia:8500
Change-Id: Ic9e485072202534ae2aa702daa4cffe4b7400d03
Reviewed-on: https://skia-review.googlesource.com/c/166805
Auto-Submit: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
1 file changed