Looks like it's just enumerating platforms and there's no case for Fuchsia.

Thanks for looking into it. Feel free to disable the tests in the meanwhile
and assign this to me. I will get to it tmr. jam@ has a change in CQ (
https://chromium-review.googlesource.com/729562) which may conflict.

We don't have NetworkChangeNotifier on Fuchsia currently, so this is likely the reason these tests fail.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d19d0f0fed7546f9edddd3d338ff9d842d327e03

commit d19d0f0fed7546f9edddd3d338ff9d842d327e03
Author: Helen Li <xunjieli@chromium.org>
Date: Mon Oct 23 13:49:57 2017

Skip creating NetworkChangeNotifier if NetworkService is running in process

net::NetworkChangeNotifier's constructor checks to see that it is
the only instance in the process. If NetworkService is running in
process (which happens for some browser tests), an
NetworkChangeNotifier would have been created. If so, skip creating
a second net::NetworkChangeNotifier in NetworkService.

This CL disables the tests for OS_FUCHSIA which doesn't yet have a
platform NetworkChangeNotifier implementation.

Bug:  776599 ,  754709 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: Ia6fa294be7a6d1adb2119aa6d8743fa780216350
Reviewed-on: https://chromium-review.googlesource.com/731244
Commit-Queue: Helen Li <xunjieli@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510781}
[modify] https://crrev.com/d19d0f0fed7546f9edddd3d338ff9d842d327e03/content/network/network_service_impl.cc
[modify] https://crrev.com/d19d0f0fed7546f9edddd3d338ff9d842d327e03/content/network/network_service_unittest.cc
[modify] https://crrev.com/d19d0f0fed7546f9edddd3d338ff9d842d327e03/net/base/network_change_notifier.cc
[modify] https://crrev.com/d19d0f0fed7546f9edddd3d338ff9d842d327e03/net/base/network_change_notifier.h

Thanks Helen!

Apologies, applied the wrong component in bulk.