CL up: https://codereview.webrtc.org/2513883002/

Oleh: here's a nice infra task you can look at with help from Edward.

It basically means:
1) Setup trybots that build Chromium on our own try server that copies the recipes from Chromium, preferably from the following set of bots that we recommend running:
git cl try -m tryserver.chromium.win -b win_chromium_rel_ng
git cl try -m tryserver.chromium.android -b android_compile_dbg -b linux_android_rel_ng
git cl try -m tryserver.chromium.linux -b linux_chromium_rel_ng
git cl try -m tryserver.chromium.mac -b mac_chromium_rel_ng -b ios-device -b ios-simulator

2) Order a few new VMs from Chrome infra (go/chromeinfraticket and add Infra>Labs label), let's say 4 per platform (Win, Mac+iOS, Linux+Android) so 12 in total.

3) Check the trybots are working
4) Add them as experimental at some percentage (maybe start with 20%) in our infra/config/cq.cfg of the WebRTC repo. That way they will run for 20% of CLs automatically.
5) Look at stats on how they do, then bump to 100% once it feels safe.

FYI, this is now unblocked.

Requested machines.

https://chromium-review.googlesource.com/c/chromium/tools/build/+/832486 and https://chromium-review.googlesource.com/c/chromium/src/+/832686 in flight

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/93e880d5b6d89c2ad326b82080c7f720a8fce65f

commit 93e880d5b6d89c2ad326b82080c7f720a8fce65f
Author: Patrik Höglund <phoglund@chromium.org>
Date: Fri Jan 05 10:42:05 2018

Add new WebRTC-chromium compile trybots to waterfalls.pyl.

Bug:  chromium:666656 
Change-Id: I00f00a525204394583f79308e9a8669786a8f3be
Reviewed-on: https://chromium-review.googlesource.com/832686
Commit-Queue: Patrik Höglund <phoglund@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#527254}
[add] https://crrev.com/93e880d5b6d89c2ad326b82080c7f720a8fce65f/testing/buildbot/tryserver.webrtc.json
[modify] https://crrev.com/93e880d5b6d89c2ad326b82080c7f720a8fce65f/testing/buildbot/waterfalls.pyl
[modify] https://crrev.com/93e880d5b6d89c2ad326b82080c7f720a8fce65f/tools/mb/mb_config.pyl

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/6cb59bbc00be1a1f209e80d341f356b36062203f

commit 6cb59bbc00be1a1f209e80d341f356b36062203f
Author: Patrik Höglund <phoglund@chromium.org>
Date: Mon Jan 08 08:50:50 2018

Add Chromium compile trybots to tryserver.webrtc.

The purpose is to add a few new bots that just compile Chromium with
WebRTC. The default Chrome recipes can apply WebRTC patches already,
so no recipe work is required.

Bug: chromium:666656 
Change-Id: If01bb342ab232abca899de5f1720d4969700f87c
Reviewed-on: https://chromium-review.googlesource.com/832486
Commit-Queue: Patrik Höglund <phoglund@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>

[modify] https://crrev.com/6cb59bbc00be1a1f209e80d341f356b36062203f/masters/master.tryserver.webrtc/slaves.cfg
[modify] https://crrev.com/6cb59bbc00be1a1f209e80d341f356b36062203f/masters/master.tryserver.webrtc/master.cfg
[modify] https://crrev.com/6cb59bbc00be1a1f209e80d341f356b36062203f/scripts/slave/recipe_modules/chromium_tests/trybots.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/cd01a186decc0e571fff8b273ef7466bc9a6132e

commit cd01a186decc0e571fff8b273ef7466bc9a6132e
Author: Patrik Höglund <phoglund@chromium.org>
Date: Tue Jan 09 14:41:27 2018

Add missing WebRTC tryserver config.

Bug: chromium:666656 
Change-Id: I302cb2152b49708bac143fe597d5020e9981a314
Reviewed-on: https://chromium-review.googlesource.com/856556
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Patrik Höglund <phoglund@chromium.org>

[modify] https://crrev.com/cd01a186decc0e571fff8b273ef7466bc9a6132e/scripts/slave/recipe_modules/chromium_tests/builders.py
[add] https://crrev.com/cd01a186decc0e571fff8b273ef7466bc9a6132e/scripts/slave/recipe_modules/chromium_tests/tryserver_webrtc.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/b01f7a69ecba4f79a61f68c1156330501945167a

commit b01f7a69ecba4f79a61f68c1156330501945167a
Author: Patrik Höglund <phoglund@chromium.org>
Date: Tue Jan 09 16:05:08 2018

Fix typo in WebRTC try config.

Bug: chromium:666656 
Change-Id: I2b2917eb8fc8a8737c4bd8770ca243978086a0df
Reviewed-on: https://chromium-review.googlesource.com/857500
Commit-Queue: Patrik Höglund <phoglund@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>

[modify] https://crrev.com/b01f7a69ecba4f79a61f68c1156330501945167a/scripts/slave/recipe_modules/chromium_tests/tryserver_webrtc.py

They appear to work. I was concerned they were slow, but that was just because it was the first checkout. Now that the bots are warmed up they appear to take 20-30 minutes to run on a small CL. That's still slower than the average WebRTC bot which takes 15 minutes or so on average, but I think we can live with that.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/8a330d366e1040503f085cce2f316720f08f0466

commit 8a330d366e1040503f085cce2f316720f08f0466
Author: Patrik Höglund <phoglund@chromium.org>
Date: Thu Jan 11 15:02:43 2018

Set phoglund as owner for webrtc tryserver.

Bug:  chromium:666656 
Change-Id: Iaf1d1c4be7c98abd850a3df33806024ba5f5c67a
R=jbudorick@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/861622
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Patrik Höglund <phoglund@chromium.org>

[modify] https://crrev.com/8a330d366e1040503f085cce2f316720f08f0466/scripts/slave/recipe_modules/chromium_tests/OWNERS

The following revision refers to this bug:
  https://webrtc.googlesource.com/src.git/+/f0839f2c96d5495456022ecb306e6356a238459a

commit f0839f2c96d5495456022ecb306e6356a238459a
Author: Patrik Höglund <phoglund@webrtc.org>
Date: Fri Jan 12 09:41:51 2018

Make new Chromium compile trybots mandatory.

These new bots will check all that all WebRTC patches compile in
Chromium before landing. They will not run tests, but this should be
enough to catch the majority of the errors.

Expected cycle time is ~30 minutes, so they may slow down the CQ.
I will monitor this so the average cycle time isn't too adversely
affected.

Bug:  chromium:666656 
Change-Id: I09c0409ea614570b3c28bf4be3644dfffacb424c
Reviewed-on: https://webrtc-review.googlesource.com/39006
Commit-Queue: Patrik Höglund <phoglund@webrtc.org>
Reviewed-by: Edward Lemur <ehmaldonado@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21594}
[modify] https://crrev.com/f0839f2c96d5495456022ecb306e6356a238459a/infra/config/cq.cfg

Or actually, the buildbucket patch still needs to land.

The bots do build up pending times during peak hours for android, linux and win, so I need a few more win/linux bots...

Ordered more machines.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/3c1df62264dfeb4ddeed95bdfd79ea59aacfb000

commit 3c1df62264dfeb4ddeed95bdfd79ea59aacfb000
Author: Patrik Höglund <phoglund@chromium.org>
Date: Wed Jan 17 12:17:19 2018

Add 2 more slaves to win and linux/android each

This should help reduce the pending times on the WebRTC chromium
compile trybots.

Bug: chromium:666656 ,chromium:802180
Change-Id: I2a579e514d4da0d115b0f2eb9e5d386fc323f762
Reviewed-on: https://chromium-review.googlesource.com/870110
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Patrik Höglund <phoglund@chromium.org>

[modify] https://crrev.com/3c1df62264dfeb4ddeed95bdfd79ea59aacfb000/masters/master.tryserver.webrtc/slaves.cfg

I looked at the stats, and the new bots are no longer sticking out in build cycle time and pending times. They do have much longer pre-test cycle times than the WebRTC bots, but they do have to check out a lot more stuff. Also, they occasionally queue up during peak hours but no worse than the slower WebRTC bots such as baremetal. I think we're fine.

I will not add iOS bots to these trybots either. It's an entirely separate system and would take research. The webrtc.org code isn't even used by Chrome on iOS, anyway; it has to use Safari, if anything.