GitLab

This reverts commit 79a6ffe5 and
introduces test implementations of the scheduler and network client.
These test implementations ensure the Feed stops trying to load content
so that Chrome can finish starting up.

BUG=854866

Change-Id: I41da8b433a7ab3b7a6786a3be2960598f3e3479e
Reviewed-on: https://chromium-review.googlesource.com/1162771
Commit-Queue: Theresa <twellington@chromium.org>
Reviewed-by: Sky Malice <skym@chromium.org>
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581254}