GitLab

Add a new state CANCELING for showing a continuous progress bar when
waiting for a cancel request to complete.

http://screen/BJsFQbdZFDZscdV

Bug: 1059779
Change-Id: I98ee9863367b602b3a29f8cd3583db36112cc081
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2561505
Commit-Queue: Gavin Williams <gavinwill@chromium.org>
Reviewed-by: Jesse Schettler <jschettler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832423}