Fix WebURLLoaderMockFactoryImpl::RunUntilIdle

This can lead to nested messageloops and it's working by accident
currently due to the interactions with the way the SequenceManager and
the MessageLoop work.

Bug: 863341, 891670
Change-Id: I7b01059638e2ba8a136a7daac387467aab517a3c
Reviewed-on: https://chromium-review.googlesource.com/c/1347353
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Commit-Queue: Alex Clarke <alexclarke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610394}
1 file changed