GitLab

Drive-by: update video tests to return correct promise and improve
style.

Bug: 1052765
Change-Id: Id1c31b577f0431b2073f0ae486926283aca41759
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2132200
Commit-Queue: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Marina Ciocea <marinaciocea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#755919}