GitLab

This enables WebAuthn flow to be properly cancelled on ChromeOS.

      timeout and observe that ChromeOS UI is dismissed (and Chrome
      shows the timeout message).

Bug: 1150656
Test: Started MakeCredential with test website then waited till
Change-Id: I5403b03dd99fe329ea9009f7544bfefade39815c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2548185
Commit-Queue: Yicheng Li <yichengli@chromium.org>
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Cr-Commit-Position: refs/heads/master@{#829068}