components_unittests failing on chromium.linux/Linux Tests

Builders failed on: 
- Linux Tests: 
  https://build.chromium.org/p/chromium.linux/builders/Linux%20Tests


Linux Tests are flaky on components_unittests starting around build #59620. http://uberchromegw/i/chromium.linux/builders/Linux%20Tests/builds/59620/steps/components_unittests


Failure Reason:

[ RUN      ] FieldTrialsProviderTest.ProvideSyntheticTrials
../../components/metrics/field_trials_provider_unittest.cc:38: Failure
      Expected: (sizeof(ArraySizeHelper(kFieldTrialIds))) + (sizeof(ArraySizeHelper(kSyntheticTrials)))
      Which is: 5
To be equal to: static_cast<size_t>(system_profile.field_trial_size())
      Which is: 6
[  FAILED  ] FieldTrialsProviderTest.ProvideSyntheticTrials (0 ms)
[ RUN      ] FieldTrialsProviderTest.ProvideSyntheticTrials
../../components/metrics/field_trials_provider_unittest.cc:38: Failure
      Expected: (sizeof(ArraySizeHelper(kFieldTrialIds))) + (sizeof(ArraySizeHelper(kSyntheticTrials)))
      Which is: 5
To be equal to: static_cast<size_t>(system_profile.field_trial_size())
      Which is: 6
[  FAILED  ] FieldTrialsProviderTest.ProvideSyntheticTrials (0 ms)
[ RUN      ] FieldTrialsProviderTest.ProvideSyntheticTrials
../../components/metrics/field_trials_provider_unittest.cc:38: Failure
      Expected: (sizeof(ArraySizeHelper(kFieldTrialIds))) + (sizeof(ArraySizeHelper(kSyntheticTrials)))
      Which is: 5
To be equal to: static_cast<size_t>(system_profile.field_trial_size())
      Which is: 6
[  FAILED  ] FieldTrialsProviderTest.ProvideSyntheticTrials (1 ms)
[ RUN      ] FieldTrialsProviderTest.ProvideSyntheticTrials
../../components/metrics/field_trials_provider_unittest.cc:38: Failure
      Expected: (sizeof(ArraySizeHelper(kFieldTrialIds))) + (sizeof(ArraySizeHelper(kSyntheticTrials)))
      Which is: 5
To be equal to: static_cast<size_t>(system_profile.field_trial_size())
      Which is: 6
[  FAILED  ] FieldTrialsProviderTest.ProvideSyntheticTrials (0 ms)

Assigning to holte@ due to recently landed http://crrev.com/c/576154.