refactor setBoundsCheck() a bit

This doesn't change anything practical, but makes sure setBoundsCheck()
and setBoundsNoCheck() run through the same logic.

Bug: skia:7967

Change-Id: Ic78e2ebd5ebf46d6251c84ba93dcd397a97816fc
Reviewed-on: https://skia-review.googlesource.com/129060
Auto-Submit: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
1 file changed