DM: duh, don't calculate digests unless we're going to look at them.

This doesn't cut the runtime significantly (~6s either way) but it does cut the CPU time down from ~10s to ~6s.

BUG=
R=bungeman@google.com

Author: mtklein@google.com

Review URL: https://codereview.chromium.org/27476007

git-svn-id: http://skia.googlecode.com/svn/trunk@11826 2bbb7eff-a529-9590-31e7-b0007b416f81
6 files changed