Can you provide links or pastes from the failure?

https://uberchromegw.corp.google.com/i/internal.bling.main/builders/canary-device

https://uberchromegw.corp.google.com/i/internal.bling.main/builders/canary-device/builds/1049/steps/ios_chrome_settings_egtests%20%28iPad%20Air%20iOS%2010.0.1%29%20on%20iOS-10.0.1

FirstRunTestCase.testTermsAndConditions is different than the others. It's just that the test expects Chromium branding.

For the SettingsTestCases, I am still investigating, btu they are all calling  -(void)assertsMetricsPrefsForService:(MetricsServiceType)serviceType

In there:
// Split here:  Official build vs. Development build.
// Official builds allow recording and uploading of data, honoring the
// metrics prefs.  Development builds should never record or upload data.
#if defined(GOOGLE_CHROME_BUILD)

So I'll investigate more in that direction.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/973aa79155460a0ff6e7c36452ab18dd9c4ec960

commit 973aa79155460a0ff6e7c36452ab18dd9c4ec960
Author: lpromero <lpromero@chromium.org>
Date: Mon Mar 13 18:27:58 2017

Fix FirstRunTestCase.testTermsAndConditions on official

The test expected Chromium branded, which failed on Official builds.

BUG=  700814  
R=kkhorimoto@chromium.org
TBR=gambard@chromium.org

Review-Url: https://codereview.chromium.org/2745123002
Cr-Commit-Position: refs/heads/master@{#456437}

[modify] https://crrev.com/973aa79155460a0ff6e7c36452ab18dd9c4ec960/ios/chrome/browser/ui/first_run/first_run_egtest.mm

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/502a0b3e580685f93a0319f433bcf150ddb6806d

commit 502a0b3e580685f93a0319f433bcf150ddb6806d
Author: lpromero <lpromero@chromium.org>
Date: Fri Mar 24 18:05:31 2017

Fix SettingsTestCase.testBreakpadReportingFirstLaunch on Official

Breakpad sets its state with dispatch_async:
https://cs.chromium.org/chromium/src/breakpad/src/client/ios/BreakpadController.mm?sq=package:chromium&dr&l=174
In EarlGrey tests, wait for the state to be consistent before
proceeding.

BUG= 700839 
R=olivierrobin@chromium.org

Review-Url: https://codereview.chromium.org/2760973002
Cr-Commit-Position: refs/heads/master@{#459474}

[modify] https://crrev.com/502a0b3e580685f93a0319f433bcf150ddb6806d/ios/chrome/browser/ui/settings/settings_egtest.mm

Still failing
https://uberchromegw.corp.google.com/i/internal.bling.main/builders/canary-device/builds/1064

https://codereview.chromium.org/2775403003/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4e751ec73a63ac0600f1b3fa758a864cc29da52b

commit 4e751ec73a63ac0600f1b3fa758a864cc29da52b
Author: lpromero <lpromero@chromium.org>
Date: Tue Mar 28 14:19:52 2017

Wait for WWAN state to propagate to Breakpad in EG tests

The issue is that SetWWANStateTo calls ultimately to an asynchronous
method in Breakpad (-setUploadingEnabled:). So we need to wait for the
propagation before asserting behaviors and state.

BUG= 700839 
R=olivierrobin@google.com

Review-Url: https://codereview.chromium.org/2775403003
Cr-Commit-Position: refs/heads/master@{#460095}

[modify] https://crrev.com/4e751ec73a63ac0600f1b3fa758a864cc29da52b/ios/chrome/browser/ui/settings/settings_egtest.mm

Should cycle green for these tests next time.

Still fails on canary

Anything else we can try to do to fix these tests?

I haven't had time to look at it again, but I am kind of out of ideas.

The issue is that there is still a race condition, even after the drainUntilIdle. Which makes sense.

https://codereview.chromium.org/2827313002 uses the breakpad controller queue to dispatch a barrier block to create a "wait" method, to wait for the BreakpadController to finish updating its state before proceeding.

Thanks for digging into this!

Replace drainUntilIdle with a dispatch_barrier_sync for Breakpad tests

drainUntilIdle was a crutch because it didn't fully eliminate the race
condition between Breakpad setting its state on its own queue and the
tests.
This CL adds a test method to get the BreakpadController queue and
dispatches a barrier block on it to wait until the BreakpadController
updated its state.

Previously:
https://codereview.chromium.org/2760973002/
https://codereview.chromium.org/2775403003/

BUG= 700839 
R=baxley@chromium.org
CC=olivierrobin@chromium.or

Review-Url: https://codereview.chromium.org/2827313002
Cr-Commit-Position: refs/heads/master@{#466065}
Committed: https://chromium.googlesource.com/chromium/src/+/5895ccc48d4395a1b5359a6ca8ca9eb654d4cd3d



I will verify on tomorrow's official builds.

Cycled green! Finally :)

[Auto-generated comment by a script] We noticed that this issue is targeted for M-59; it appears the fix may have landed after branch point, meaning a merge might be required. Please confirm if a merge is required here - if so add Merge-Request-59 label, otherwise remove Merge-TBD label. Thanks.

This would turn beta-device green.

Your change meets the bar and is auto-approved for M59. Please go ahead and merge the CL to branch 3071 manually. Please contact milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), gkihumba@(ChromeOS), Abdul Syed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/20d59625dac84ed76c03f45b49a1f3979e5f9be1

commit 20d59625dac84ed76c03f45b49a1f3979e5f9be1
Author: Louis Romero <lpromero@google.com>
Date: Fri Apr 21 10:30:04 2017

Replace drainUntilIdle with a dispatch_barrier_sync for Breakpad tests

drainUntilIdle was a crutch because it didn't fully eliminate the race
condition between Breakpad setting its state on its own queue and the
tests.
This CL adds a test method to get the BreakpadController queue and
dispatches a barrier block on it to wait until the BreakpadController
updated its state.

Previously:
https://codereview.chromium.org/2760973002/
https://codereview.chromium.org/2775403003/

BUG= 700839 
R=baxley@chromium.org
CC=olivierrobin@chromium.or

Review-Url: https://codereview.chromium.org/2827313002
Cr-Commit-Position: refs/heads/master@{#466065}
(cherry picked from commit 5895ccc48d4395a1b5359a6ca8ca9eb654d4cd3d)

Review-Url: https://codereview.chromium.org/2837483003 .
Cr-Commit-Position: refs/branch-heads/3071@{#119}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}

[modify] https://crrev.com/20d59625dac84ed76c03f45b49a1f3979e5f9be1/ios/chrome/browser/ui/settings/settings_egtest.mm
[modify] https://crrev.com/20d59625dac84ed76c03f45b49a1f3979e5f9be1/ios/chrome/test/app/chrome_test_util.h
[modify] https://crrev.com/20d59625dac84ed76c03f45b49a1f3979e5f9be1/ios/chrome/test/app/chrome_test_util.mm