GitLab

Some reworking how the "DNS race" works now that the initial resolve
can handle both stale and fresh and we only need to spawn a separate
call if it actually does return a stale result.

Also fix some tests that were relying on a custom HostResolver mock
that gave unintended behavior when CreateRequest() was used instead of
Resolve().

Bug: 922699
Change-Id: I349b5995f2fc5c9042f1a0387bac4018461717d4
Reviewed-on: https://chromium-review.googlesource.com/c/1435710Reviewed-by: Asanka Herath <asanka@chromium.org>
Commit-Queue: Eric Orth <ericorth@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630120}