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/+/0a6ceee97037d57f46d3de59e79cb5e85c5feb40

commit 0a6ceee97037d57f46d3de59e79cb5e85c5feb40
Author: Robbie McElrath <rmcelrath@chromium.org>
Date: Tue Jan 15 04:20:06 2019

Reenable PictureInPictureWindowControllerBrowserTest.TabIconUpdated on ChromeOS with Network Service

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.

TBR=jam

Bug:  915978 
Change-Id: Iad658402e4f1c36bd0437b715ef0fd3613ceaaad
Reviewed-on: https://chromium-review.googlesource.com/c/1407745
Reviewed-by: Robbie McElrath <rmcelrath@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622725}
[modify] https://crrev.com/0a6ceee97037d57f46d3de59e79cb5e85c5feb40/testing/buildbot/filters/mojo.fyi.chromeos.network_browser_tests.filter