GitLab

Introduce the FakeTCPConnectedSocket resolver class, used by unit tests,
to avoid duplication across multiple routines.

BUG=chromium:956783
TEST=none

Change-Id: I1ab4161de6a23790f8b6f8b3bb652701c6ad422b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2448652
Commit-Queue: Kartik Hegde <khegde@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814435}