Change HostResolverImplDnsTest.NoIPv6OnWifi to no longer leak

Change HostResolverImplDnsTest.NoIPv6OnWifi to no longer leak
deleted resolvers into the network change notifier.

BUG=729320, 728808
Review-Url: https://codereview.chromium.org/2916903006
Cr-Commit-Position: refs/heads/master@{#477013}
Committed: https://chromium.googlesource.com/chromium/src/+/ce64e673564b8a2b0912c07567e96c97aa4dca06

[Ryan Hamilton, 2017-06-03 14:56:19]

Description was changed from

==========
Change HostResolverImplDnsTest.NoIPv6OnWifi to no longer leak
deleted resolvers into the network change notifier.

BUG=729320
==========

to

==========
Change HostResolverImplDnsTest.NoIPv6OnWifi to no longer leak
deleted resolvers into the network change notifier.

BUG=729320,728808
==========

[Ryan Hamilton, 2017-06-03 15:09:58]

rch@chromium.org changed reviewers:
+ jri@chromium.org, mgersh@chromium.org

[Ryan Hamilton, 2017-06-03 15:09:59]

mgersh: I think you originally wrote this test and seem to be the owner of
crbug.com/728808. It turns out this test causes a user-after-free. Please take a
look

jri: I finally got to the bottom of this!

[mgersh, 2017-06-05 14:44:42]

Wow, thanks for figuring that out! lgtm.

[Ryan Hamilton, 2017-06-05 16:48:18]

The CQ bit was checked by rch@chromium.org

[commit-bot: I haz the power, 2017-06-05 16:48:31]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-05 17:42:02]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1496681298464700,
"parent_rev": "633b706243f9c67ff68260c0a5571b8c79170e45", "commit_rev":
"ce64e673564b8a2b0912c07567e96c97aa4dca06"}

[commit-bot: I haz the power, 2017-06-05 17:42:12]

Description was changed from

==========
Change HostResolverImplDnsTest.NoIPv6OnWifi to no longer leak
deleted resolvers into the network change notifier.

BUG=729320,728808
==========

to

==========
Change HostResolverImplDnsTest.NoIPv6OnWifi to no longer leak
deleted resolvers into the network change notifier.

BUG=729320,728808

Review-Url: https://codereview.chromium.org/2916903006
Cr-Commit-Position: refs/heads/master@{#477013}
Committed:
https://chromium.googlesource.com/chromium/src/+/ce64e673564b8a2b0912c07567e9...
==========

[commit-bot: I haz the power, 2017-06-05 17:42:14]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/ce64e673564b8a2b0912c07567e9...