hi clarke, giving you the bug since you are really familiar with extensions. Not sure if you have time.

Make it available if you can't get to it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dccf844abebc5b18353b40fe9a8eb09ae441bd5e

commit dccf844abebc5b18353b40fe9a8eb09ae441bd5e
Author: Clark DuVall <cduvall@chromium.org>
Date: Thu Aug 16 23:25:44 2018

Convert dns_api.cc to mojo host resolver

Bug:  874658 
Cq-Include-Trybots: luci.chromium.try:linux_mojo
Change-Id: I576d2877ec71df8e489d349916f758ba6fe74263
Reviewed-on: https://chromium-review.googlesource.com/1176725
Reviewed-by: Will Harris <wfh@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583878}
[modify] https://crrev.com/dccf844abebc5b18353b40fe9a8eb09ae441bd5e/chrome/browser/net/network_context_configuration_browsertest.cc
[modify] https://crrev.com/dccf844abebc5b18353b40fe9a8eb09ae441bd5e/content/public/test/browser_test_base.cc
[modify] https://crrev.com/dccf844abebc5b18353b40fe9a8eb09ae441bd5e/content/public/test/network_service_test_helper.cc
[modify] https://crrev.com/dccf844abebc5b18353b40fe9a8eb09ae441bd5e/extensions/browser/api/dns/dns_api.cc
[modify] https://crrev.com/dccf844abebc5b18353b40fe9a8eb09ae441bd5e/extensions/browser/api/dns/dns_api.h
[modify] https://crrev.com/dccf844abebc5b18353b40fe9a8eb09ae441bd5e/extensions/browser/api/dns/dns_apitest.cc
[modify] https://crrev.com/dccf844abebc5b18353b40fe9a8eb09ae441bd5e/services/network/public/mojom/network_service_test.mojom

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8de01f72527182872ed0162cfa5c14487e344b95

commit 8de01f72527182872ed0162cfa5c14487e344b95
Author: Kentaro Hara <haraken@chromium.org>
Date: Fri Aug 17 04:08:00 2018

Revert "Convert dns_api.cc to mojo host resolver"

This reverts commit dccf844abebc5b18353b40fe9a8eb09ae441bd5e.

Reason for revert: Broke some browser_tests on Mac.

https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Mac10.13%20Tests%20%28dbg%29/4738

Original change's description:
> Convert dns_api.cc to mojo host resolver
> 
> Bug:  874658 
> Cq-Include-Trybots: luci.chromium.try:linux_mojo
> Change-Id: I576d2877ec71df8e489d349916f758ba6fe74263
> Reviewed-on: https://chromium-review.googlesource.com/1176725
> Reviewed-by: Will Harris <wfh@chromium.org>
> Reviewed-by: John Abd-El-Malek <jam@chromium.org>
> Commit-Queue: Clark DuVall <cduvall@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#583878}

TBR=jam@chromium.org,wfh@chromium.org,ericorth@chromium.org,cduvall@chromium.org

Change-Id: Id845006ad303fca63c7c681fd259d3db379dfddd
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  874658 
Cq-Include-Trybots: luci.chromium.try:linux_mojo
Reviewed-on: https://chromium-review.googlesource.com/1179383
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583955}
[modify] https://crrev.com/8de01f72527182872ed0162cfa5c14487e344b95/chrome/browser/net/network_context_configuration_browsertest.cc
[modify] https://crrev.com/8de01f72527182872ed0162cfa5c14487e344b95/content/public/test/browser_test_base.cc
[modify] https://crrev.com/8de01f72527182872ed0162cfa5c14487e344b95/content/public/test/network_service_test_helper.cc
[modify] https://crrev.com/8de01f72527182872ed0162cfa5c14487e344b95/extensions/browser/api/dns/dns_api.cc
[modify] https://crrev.com/8de01f72527182872ed0162cfa5c14487e344b95/extensions/browser/api/dns/dns_api.h
[modify] https://crrev.com/8de01f72527182872ed0162cfa5c14487e344b95/extensions/browser/api/dns/dns_apitest.cc
[modify] https://crrev.com/8de01f72527182872ed0162cfa5c14487e344b95/services/network/public/mojom/network_service_test.mojom

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9690e08467150d094fd74f3db673c995cec2b78c

commit 9690e08467150d094fd74f3db673c995cec2b78c
Author: Clark DuVall <cduvall@chromium.org>
Date: Fri Aug 17 17:58:22 2018

Reland "Convert dns_api.cc to mojo host resolver"

This is a reland of dccf844abebc5b18353b40fe9a8eb09ae441bd5e

This was reverted because NetworkContextConfigurationBrowserTests
were failing on Mac due to  crbug.com/843324 . This is because those
tests call AddSimulatedFailure() on the host resolver, which now
sends those rules to NetworkServiceTest (which doesn't work on Mac).
I disabled the NetworkContextConfigurationBrowserTests on Mac that
run with network service enabled.

Original change's description:
> Convert dns_api.cc to mojo host resolver
>
> Bug:  874658 
> Cq-Include-Trybots: luci.chromium.try:linux_mojo
> Change-Id: I576d2877ec71df8e489d349916f758ba6fe74263
> Reviewed-on: https://chromium-review.googlesource.com/1176725
> Reviewed-by: Will Harris <wfh@chromium.org>
> Reviewed-by: John Abd-El-Malek <jam@chromium.org>
> Commit-Queue: Clark DuVall <cduvall@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#583878}

TBR=wfh@chromium.org,jam@chromium.org

Bug:  874658 
Change-Id: Ib26c612a450a48818a10f817bd2d309292d4c9ea
Cq-Include-Trybots: luci.chromium.try:linux_mojo
Reviewed-on: https://chromium-review.googlesource.com/1179922
Reviewed-by: Clark DuVall <cduvall@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584122}
[modify] https://crrev.com/9690e08467150d094fd74f3db673c995cec2b78c/chrome/browser/net/network_context_configuration_browsertest.cc
[modify] https://crrev.com/9690e08467150d094fd74f3db673c995cec2b78c/content/public/test/browser_test_base.cc
[modify] https://crrev.com/9690e08467150d094fd74f3db673c995cec2b78c/content/public/test/network_service_test_helper.cc
[modify] https://crrev.com/9690e08467150d094fd74f3db673c995cec2b78c/extensions/browser/api/dns/dns_api.cc
[modify] https://crrev.com/9690e08467150d094fd74f3db673c995cec2b78c/extensions/browser/api/dns/dns_api.h
[modify] https://crrev.com/9690e08467150d094fd74f3db673c995cec2b78c/extensions/browser/api/dns/dns_apitest.cc
[modify] https://crrev.com/9690e08467150d094fd74f3db673c995cec2b78c/services/network/public/mojom/network_service_test.mojom