GitLab

Remove the file and migrate any needed selectors to custom elements
that use them, and the main file_manager.css file.

Also removes the file reference in the python testing script.

Bug: 947388
Change-Id: I0673fa6cb819fdee0f50cc6749e87e1e25020430
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1691949
Commit-Queue: Alex Danilo <adanilo@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676221}