GitLab

Screenshots: https://imgur.com/a/mcoKkKc
Specs: https://docs.google.com/presentation/d/1kJoBzf_HGYK-_FAJPAjD67TW8224dCPLA6dAhlDmysk/edit#slide=id.g471d243f08_0_874

There's still a bit of work to be done (notably: buttons),
but this gets us closer to Namrata's mocks.

To run locally, use --enable-features=WebUIDarkMode --force-dark-mode

BUG=883049
R=hcarmona@chromium.org

Change-Id: I232adf9b487d8be2042c5123484fdb6f87da13c4
Reviewed-on: https://chromium-review.googlesource.com/c/1377147Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Commit-Queue: Dan Beam <dbeam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619893}