Non-asan stack traces:

[ RUN      ] ResourceSchedulerTest.SchedulerYieldFieldTrialParams
../../services/network/resource_scheduler_unittest.cc:81: Failure
Value of: base::FieldTrialParamAssociator::GetInstance()->AssociateFieldTrialParams( kTrialName, kGroupName, params)
  Actual: false
Expected: true
Stack trace:
#0 0x000000a59a3c testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#1 0x000000a59419 testing::internal::AssertHelper::operator=()
#2 0x000000517a39 network::(anonymous namespace)::ResourceSchedulerTest_SchedulerYieldFieldTrialParams_Test::TestBody()

../../services/network/resource_scheduler_unittest.cc:565: Failure
Expected equality of these values:
  42
  scheduler_->yield_time().InMilliseconds()
    Which is: 0
Stack trace:
#0 0x000000a59a3c testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#1 0x000000a59419 testing::internal::AssertHelper::operator=()
#2 0x000000517cae network::(anonymous namespace)::ResourceSchedulerTest_SchedulerYieldFieldTrialParams_Test::TestBody()

../../services/network/resource_scheduler_unittest.cc:566: Failure
Expected equality of these values:
  1
  scheduler_->max_requests_before_yielding()
    Which is: 5
Stack trace:
#0 0x000000a59a3c testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#1 0x000000a59419 testing::internal::AssertHelper::operator=()
#2 0x000000517e49 network::(anonymous namespace)::ResourceSchedulerTest_SchedulerYieldFieldTrialParams_Test::TestBody()

../../services/network/resource_scheduler_unittest.cc:584: Failure
Value of: request2->started()
  Actual: true
Expected: false
Stack trace:
#0 0x000000a59a3c testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#1 0x000000a59419 testing::internal::AssertHelper::operator=()
#2 0x000000518193 network::(anonymous namespace)::ResourceSchedulerTest_SchedulerYieldFieldTrialParams_Test::TestBody()

[  FAILED  ] ResourceSchedulerTest.SchedulerYieldFieldTrialParams (15 ms)

I am not familiar with these tests but Tarun seems to have made a number of changes recently.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/68c2b0e8549fd6ef98e6d4da9ecdb9841fd6ace4

commit 68c2b0e8549fd6ef98e6d4da9ecdb9841fd6ace4
Author: Tarun Bansal <tbansal@chromium.org>
Date: Wed May 30 06:28:57 2018

Fix flaky resource scheduler test

Clear the field trial params before running the test to ensure
minimal cross-test conflicts.

Bug:  846514 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I116147d9df7a015eb3cc36a01fb1aa6b43dbc717
Reviewed-on: https://chromium-review.googlesource.com/1077813
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562752}
[modify] https://crrev.com/68c2b0e8549fd6ef98e6d4da9ecdb9841fd6ace4/services/network/resource_scheduler_unittest.cc

I could not repro the flakiness on my desktiop, but I submitted a CL in #4 that should hopefully fix it.