GitLab

Check where the shell extensions are actually registered instead of only
looking at the list of Approved shell extensions.

Change-Id: I3257106060f4775fe83f8af322c007e022064630
Reviewed-on: https://chromium-review.googlesource.com/1197352Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Greg Thompson <grt@chromium.org>
Commit-Queue: Patrick Monette <pmonette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590482}