The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1e864965d203c5fa51883a1de785a110107b105b

commit 1e864965d203c5fa51883a1de785a110107b105b
Author: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Date: Wed Aug 22 04:24:43 2018

goma_client_type to specify which goma client to use.

Instead of boolean flag use_goma_canary, let me make it use
string property to allow us to specify arbitrary cipd ref to use.

Bug: 874754
Bug:  876583 
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I6ad5233986b0b7d4a98a0857500a490f2ffc3a39
Reviewed-on: https://chromium-review.googlesource.com/1183042
Commit-Queue: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Reviewed-by: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: smut <smut@google.com>
Cr-Commit-Position: refs/heads/master@{#584960}
[modify] https://crrev.com/1e864965d203c5fa51883a1de785a110107b105b/ios/build/bots/chromium.fyi/ios-device-goma-canary-clobber.json

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/6543bba085db462c0f889d9eb9092ca79bd83791

commit 6543bba085db462c0f889d9eb9092ca79bd83791
Author: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Date: Thu Aug 23 06:20:09 2018

ios json config file use goma_client_type instead of use_goma_canary.

To make the builder choose arbitrary ref, let me make it use
goma_client_type instead of use_goma_canary.

Bug:  876583 
Change-Id: I40917479dc4dbb3171662cada5c6d8a21e95c8fd
Reviewed-on: https://chromium-review.googlesource.com/1184586
Commit-Queue: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Reviewed-by: smut <smut@google.com>

[modify] https://crrev.com/6543bba085db462c0f889d9eb9092ca79bd83791/scripts/slave/README.recipes.md
[modify] https://crrev.com/6543bba085db462c0f889d9eb9092ca79bd83791/scripts/slave/recipes/ios/unified_builder_tester.py
[modify] https://crrev.com/6543bba085db462c0f889d9eb9092ca79bd83791/scripts/slave/recipe_modules/ios/api.py
[modify] https://crrev.com/6543bba085db462c0f889d9eb9092ca79bd83791/scripts/slave/recipes/ios/unified_builder_tester.expected/goma_canary.json

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/81eda3bd78bff97a4c074e7a9ed78b8f3a2e2fe7

commit 81eda3bd78bff97a4c074e7a9ed78b8f3a2e2fe7
Author: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Date: Wed Aug 29 02:34:14 2018

Deprecate "use_goma_canary".

Since recipe have already changed to use "goma_client_type",
we do not need to set "use_goma_canary" any more.

Bug:  876583 
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: Icd4dff579f97deee156dce8f4cbbd84aa5ffb5ee
Reviewed-on: https://chromium-review.googlesource.com/1192471
Commit-Queue: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Reviewed-by: smut <smut@google.com>
Cr-Commit-Position: refs/heads/master@{#587001}
[modify] https://crrev.com/81eda3bd78bff97a4c074e7a9ed78b8f3a2e2fe7/ios/build/bots/chromium.fyi/ios-device-goma-canary-clobber.json