Factor out `validate` into separate method.

Change-Id: I7362e16182d42c971a2cb5bdcbdc242ef900d6b5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/312493
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
1 file changed