GitLab

Currently, user interface information is low and scattered. This document
will centralize and explain the types and limits to extension UI.

Bug: None
Change-Id: Ia6acac35fe731b6e76134239202194201e4a9edb
Reviewed-on: https://chromium-review.googlesource.com/768621
Commit-Queue: Crystal Lambert <crystallambert@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543833}