External CRXs must be crx3s

Bug: 740715
Change-Id: Iff24269bfb60bb8c300bd580fd94db468e8f6b8a
Reviewed-on: https://chromium-review.googlesource.com/c/1422593
Auto-Submit: Joshua Pawlicki <waffles@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Joshua Pawlicki <waffles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624300}
1 file changed