Modernize host resolution in NetworkQualityEstimatorUtil

Also improved MockHostResolver's handling of LOCAL_ONLY requests.

Bug: 922699
Change-Id: Ib5c94c1212ff06ddcbe97132993702b668e3ece7
Reviewed-on: https://chromium-review.googlesource.com/c/1457464
Commit-Queue: Eric Orth <ericorth@chromium.org>
Auto-Submit: Eric Orth <ericorth@chromium.org>
Reviewed-by: Asanka Herath <asanka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#631841}
4 files changed