Working on this

Some of these tests may be somewhat redundant with new tests I added to NetworkContextBrowsertests.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c4f55f716ef3513c76ae67498d00c156fa554abc

commit c4f55f716ef3513c76ae67498d00c156fa554abc
Author: Sergio Villar Senin <svillar@igalia.com>
Date: Thu Jul 19 07:49:15 2018

Migrate chrome/browser/net/proxy_browsertest.cc to SimpleURLLoader

This CL moves proxy_browsertest.cc away from URLFetcher, replacing it by
SimpleURLLoader.

Bug:  844915 
Change-Id: Id0fd3ec4168f8b1c272906e6620c11b5418d2f54
Reviewed-on: https://chromium-review.googlesource.com/1141948
Commit-Queue: Sergio Villar <svillar@igalia.com>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576413}
[modify] https://crrev.com/c4f55f716ef3513c76ae67498d00c156fa554abc/chrome/browser/net/proxy_browsertest.cc

We can close this now

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/aa6d8593a3ff0cbede6f25317704576bebe84654

commit aa6d8593a3ff0cbede6f25317704576bebe84654
Author: John Abd-El-Malek <jam@chromium.org>
Date: Wed Aug 08 15:57:07 2018

Enable now passing browser_tests with network service.

Bug:  769401 , 865350 , 844915 ,773295
Cq-Include-Trybots: luci.chromium.try:linux_mojo
Change-Id: Ie7c87877597686927a401b64120c444c79a8912c
Reviewed-on: https://chromium-review.googlesource.com/1166593
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581577}
[modify] https://crrev.com/aa6d8593a3ff0cbede6f25317704576bebe84654/testing/buildbot/filters/mojo.fyi.network_browser_tests.filter