Fix a DCHECK in content_browsertests for FontUniqueNameLookup

Navigating to a URL and waiting for that to complete
requires sync primitives.

Change-Id: Iae111ac9ee2521de4054f82829f030f797cfaac4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1627358
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Commit-Queue: Dominik Röttsches <drott@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662991}
1 file changed