I'm not able to reproduce any flakiness locally, I can't find logs from when it was flaky, and a lot of ChromeOS Network Service issues have been fixed since this bug was created, so I'm going to re-enable this test and see if the flakiness is still happening on any of the build bots.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/015093d2b21d19ad1c8022f9659bc4454b8a26a6

commit 015093d2b21d19ad1c8022f9659bc4454b8a26a6
Author: Robbie McElrath <rmcelrath@chromium.org>
Date: Wed Jan 16 04:54:10 2019

Reenable DevToolsSanityTest.DisposeEmptyBrowserContext on ChromeOS with NetworkService

At one point this test was flaky on ChromeOS with the network service
enabled, but I'm not able to reproduce any flakiness locally, I can't
find logs from when it was flaky, and a lot of ChromeOS network service
issues have been fixed in the past few months, so I'm going to
re-enable this test and see if the flakiness is still happening on any
of the build bots.

Bug:  915977 
Change-Id: Ia6266c51d6c622697c0771ee88664ac88795eed8
TBR: jam@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/c/1407950
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Robbie McElrath <rmcelrath@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623112}
[modify] https://crrev.com/015093d2b21d19ad1c8022f9659bc4454b8a26a6/testing/buildbot/filters/mojo.fyi.chromeos.network_browser_tests.filter