The general plan is:

1) Create cros tryjob command (not strictly required, but good cleanup).
2) Support optional swarming scheduling from cros tryjob.
3) Move all tryjob bots to swarming bool, make --swarm the only behavior.
4) Shutdown tryjob waterfall.

Known issues:
  Audit everything using waterfall value. Rethink.
  "production" builds, especially CIDB instance selection.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/chromite/+/0f51564af246c954efaeabe853d5378043b1f950

commit 0f51564af246c954efaeabe853d5378043b1f950
Author: Don Garrett <dgarrett@google.com>
Date: Tue Apr 03 00:59:17 2018

cros tryjob: Switch to swarming tryjobs by default.

It is possible to opt back to "buildbot" by scheduling with
"cros tryjob --waterfall".

BUG= chromium:752342 
TEST=run_tests
     cros tryjob success-build fail-build
     cros tryjob --remote success-build fail-build
     cros tryjob --waterfall success-build fail-build

Change-Id: Iac02647871c95f2c0d260afa2ba0502841db2f2c
Reviewed-on: https://chromium-review.googlesource.com/974513
Tested-by: Don Garrett <dgarrett@chromium.org>
Trybot-Ready: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Aviv Keshet <akeshet@chromium.org>

[modify] https://crrev.com/0f51564af246c954efaeabe853d5378043b1f950/cli/cros/cros_tryjob_unittest.py
[modify] https://crrev.com/0f51564af246c954efaeabe853d5378043b1f950/cli/cros/cros_tryjob.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4c161e38fbfe5b49ed37731461f1345d6985414b

commit 4c161e38fbfe5b49ed37731461f1345d6985414b
Author: chromite-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com <chromite-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Date: Tue Apr 03 02:32:49 2018

Roll src/third_party/chromite/ b90af5c20..0f51564af (1 commit)

https://chromium.googlesource.com/chromiumos/chromite.git/+log/b90af5c203f7..0f51564af246

$ git log b90af5c20..0f51564af --date=short --no-merges --format='%ad %ae %s'
2018-03-21 dgarrett cros tryjob: Switch to swarming tryjobs by default.

Created with:
  roll-dep src/third_party/chromite
BUG= chromium:752342 


The AutoRoll server is located here: https://chromite-chromium-roll.skia.org

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


TBR=chrome-os-gardeners@chromium.org

Change-Id: Ic463ecbc145afc4cacb6ed670e17fd9c2c5ba45c
Reviewed-on: https://chromium-review.googlesource.com/991404
Reviewed-by: Chromite Chromium Autoroll <chromite-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Commit-Queue: Chromite Chromium Autoroll <chromite-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#547606}
[modify] https://crrev.com/4c161e38fbfe5b49ed37731461f1345d6985414b/DEPS

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/infra_internal/+/04067ded99cc2fda7e8a93d8a413e58fc15dee44

commit 04067ded99cc2fda7e8a93d8a413e58fc15dee44
Author: Don Garrett <dgarrett@google.com>
Date: Mon Apr 09 23:01:57 2018

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/chromite/+/10c4cfbd1e63dee0bc0f3dcae99899a12894506a

commit 10c4cfbd1e63dee0bc0f3dcae99899a12894506a
Author: Don Garrett <dgarrett@google.com>
Date: Mon Apr 09 23:07:42 2018

cros tryjob: Remove --waterfall option.

Remove the option of running a tryjob by the waterfall, since we are
shutting the waterfall down.

BUG= chromium:752342 
TEST=run_tests + 3 months swarming preview + 1 week swarming opt-out.

Change-Id: Ib380f5c15b479f3fd43ad6fafa400e06608a6c72
Reviewed-on: https://chromium-review.googlesource.com/1003059
Tested-by: Don Garrett <dgarrett@chromium.org>
Trybot-Ready: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Jacob Kopczynski <jkop@chromium.org>

[modify] https://crrev.com/10c4cfbd1e63dee0bc0f3dcae99899a12894506a/cli/cros/cros_tryjob_unittest.py
[modify] https://crrev.com/10c4cfbd1e63dee0bc0f3dcae99899a12894506a/cli/cros/cros_tryjob.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/chromite/+/9abe7552781ef5fe85f55e2496e5c5080b824538

commit 9abe7552781ef5fe85f55e2496e5c5080b824538
Author: Don Garrett <dgarrett@google.com>
Date: Mon Apr 09 23:08:17 2018

master.chromiumos.tryserver: Mark read only.

As the first step to shutting down the tryserver waterfall, mark it's
bucket as read only.

BUG= chromium:752342 

Change-Id: I1ba11f6ffc282a47721653b5c5b2446c1490a16c
Reviewed-on: https://chromium-review.googlesource.com/1003283
Reviewed-by: Nodir Turakulov <nodir@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>

[modify] https://crrev.com/9abe7552781ef5fe85f55e2496e5c5080b824538/cr-buildbucket.cfg

This request has been filed to shutdown the buildbot instance:

https://crbug.com/830975

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4d1bbb3fd11879ae03b79f844719703b9d4b959c

commit 4d1bbb3fd11879ae03b79f844719703b9d4b959c
Author: chromite-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com <chromite-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Date: Tue Apr 10 04:36:17 2018

Roll src/third_party/chromite/ 02ef76b01..871e7778e (6 commits)

https://chromium.googlesource.com/chromiumos/chromite.git/+log/02ef76b018ac..871e7778ef8b

$ git log 02ef76b01..871e7778e --date=short --no-merges --format='%ad %ae %s'
2018-03-28 pprabhu gerrit: Add 'private' subcommand.
2018-04-09 dgarrett cros tryjob: Remove --waterfall option.
2018-04-09 cmtice [clang-tidy builder] Change board from 'kahlee' to 'grunt'.
2018-04-05 mxt Revert "remove whirlwind-no-vmtest-pre-cq from default set"
2018-04-06 xzhou Update tss group test to add bootlockboxd to tss.
2018-04-06 dgarrett cbuildbot_launch: RunCbuildbot -> Cbuildbot.

Created with:
  roll-dep src/third_party/chromite
BUG=chromium:None,chromium:752342,chromium:830691,chromium:829055,chromium:None


The AutoRoll server is located here: https://chromite-chromium-roll.skia.org

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


TBR=chrome-os-gardeners@chromium.org

Change-Id: Iad8d29ecd5f47e06ce4867453d3ba4a4606d835c
Reviewed-on: https://chromium-review.googlesource.com/1004003
Commit-Queue: Chromite Chromium Autoroll <chromite-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Reviewed-by: Chromite Chromium Autoroll <chromite-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#549423}
[modify] https://crrev.com/4d1bbb3fd11879ae03b79f844719703b9d4b959c/DEPS

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/366cab97fe962e783c31dc7dc0e3034cd56cc2f8

commit 366cab97fe962e783c31dc7dc0e3034cd56cc2f8
Author: Don Garrett <dgarrett@google.com>
Date: Fri May 18 01:20:23 2018

chromiumos.tryserver: Shutting it down.

This CL removes the configuration for the chromiumos.tryserver
waterfall. The waterfall is out of production, and this can be
submitted when ready.

BUG= chromium:752342 

Change-Id: I39f854bf8027cc2662e1250d3e08f30efa907190
Reviewed-on: https://chromium-review.googlesource.com/1003636
Commit-Queue: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Ryan Tseng <hinoka@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Elliott Friedman <friedman@chromium.org>

[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/templates/buildslaves.html
[modify] https://crrev.com/366cab97fe962e783c31dc7dc0e3034cd56cc2f8/tests/masters_test.py
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/public_html/status-summary.html
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/public_html/common-resources
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/OWNERS
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/Makefile
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/master_site_config.py
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/slave_pool.json
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/templates/builder.html
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/master.cfg
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/slaves.cfg
[modify] https://crrev.com/366cab97fe962e783c31dc7dc0e3034cd56cc2f8/scripts/slave/logdog-params.pyl
[delete] https://crrev.com/85653e2bc638b1a5ce67024b9783f290346b3cba/masters/master.chromiumos.tryserver/chromiumos_tryserver_util.py