[Extensions] Don't report a bad message if the UUID is legitimate.

Bug: 955657
Change-Id: Id5124d9651d8939b8d4e37f6cfaca5b2561233d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1579639
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653659}
2 files changed