GitLab

This CL:
1. Use vector icons for zero state file results.
2. Remove unnecessary pngs
3. Refactor file icon utils.

Bug: 1067326
Change-Id: Ia64a505f4d40c7f8fcf981d7e6b976f7555de83c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2355351
Commit-Queue: Thanh Nguyen <thanhdng@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Austin Tankiang <austinct@chromium.org>
Reviewed-by: Tony Yeoman <tby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798548}