GitLab

Fix another race condition in frame detach sequence, found by stress
testing.

Change-Id: Ie342733a8627bfd36074d38b73209c751ba519dc
Reviewed-on: https://chromium-review.googlesource.com/1014506Reviewed-by: Jonathon Kereliuk <kereliuk@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551350}