GitLab

This fix a problem in the unittest where the test ends before all pending cleanup tasks have
completed.

Revert "[MemSheriff] Suppress content_unittests leaks and uninits"
This reverts commit 8ea251ca.

BUG=422087

Review URL: https://codereview.chromium.org/649513003

Cr-Commit-Position: refs/heads/master@{#299123}