GitLab

Also migrating test to use Mocha, and eliminating the need to refer to
prod code using the cert_viewer namespace. The test code previously was
replacing a prod code function as a way to intercept the response
handler and make assertions, now replaced by an event instead.

Bug: 1028829
Change-Id: Ieb5210965b311743c003a28c425f75d6ac1be462
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145934
Commit-Queue: dpapad <dpapad@chromium.org>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759518}