GitLab

The PreconnectManager issues preconnect requests only after it
preresolves a host name. If a fixed proxy configuration is in place,
there is no need to make a DNS request.

Bug: 808036
Change-Id: I15f6baf6405386fd6bd8154b2691c5b858c6e04b
Reviewed-on: https://chromium-review.googlesource.com/958913Reviewed-by: Benoit L <lizeb@chromium.org>
Commit-Queue: Alexandr Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543402}