Dark Mode: change downloads paper-progress colors

Spec: https://docs.google.com/presentation/d/1kJoBzf_HGYK-_FAJPAjD67TW8224dCPLA6dAhlDmysk/edit#slide=id.g4a64df24f4_20_0

R=aee@chromium.org
BUG=883049

Change-Id: Ice71c5ff0a9e640343a3c602154f410386944d72
Reviewed-on: https://chromium-review.googlesource.com/c/1403347
Reviewed-by: Esmael El-Moslimany <aee@chromium.org>
Commit-Queue: Dan Beam <dbeam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621344}
1 file changed