Taking this...

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/279f6c72b6960af1e3749c91c7e1fd8d2b66f0d2

commit 279f6c72b6960af1e3749c91c7e1fd8d2b66f0d2
Author: Sergio Villar Senin <svillar@igalia.com>
Date: Wed Sep 26 09:57:11 2018

[ios] Move ApplicationContext's NetworkContext to the IOSChromeIOThread

ApplicationContext it's a wrapper for an IOThread so we can safely
move the NetworkContext to the IOSChromeIOThread instance and thus
ensuring that requests are handled correctly.

Note that the unit test being removed is unnecessary, NetworkContext
guarantees that requests are torn down safely (as long as they use the
URLLoader API), so this test would be redundant.

Bug:  879772 
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: Ic585008fb4f7efd9f2b666cb13dd32d7ad226e8e
Reviewed-on: https://chromium-review.googlesource.com/1238894
Reviewed-by: David Roger <droger@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Sergio Villar <svillar@igalia.com>
Cr-Commit-Position: refs/heads/master@{#594263}
[modify] https://crrev.com/279f6c72b6960af1e3749c91c7e1fd8d2b66f0d2/ios/chrome/browser/BUILD.gn
[modify] https://crrev.com/279f6c72b6960af1e3749c91c7e1fd8d2b66f0d2/ios/chrome/browser/application_context_impl.cc
[modify] https://crrev.com/279f6c72b6960af1e3749c91c7e1fd8d2b66f0d2/ios/chrome/browser/application_context_impl.h
[modify] https://crrev.com/279f6c72b6960af1e3749c91c7e1fd8d2b66f0d2/ios/chrome/browser/ios_chrome_io_thread.h
[modify] https://crrev.com/279f6c72b6960af1e3749c91c7e1fd8d2b66f0d2/ios/chrome/browser/ios_chrome_io_thread.mm
[delete] https://crrev.com/420ec97cb6d2c364a56f1d5d7859b7bb39a8d05a/ios/chrome/browser/ios_chrome_io_thread_unittest.mm

We can close this now