GitLab

Add additional details on the permission requirements for the
tabs.captureVisibleTab() method, including that activeTab is required
for sensitive sites that the extension wouldn't otherwise be allowed
access to.

Bug: 839857
Change-Id: I6fa1a68e8dc50bc7c3553fb32740b4c963276395
Reviewed-on: https://chromium-review.googlesource.com/1138634
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575519}