It is failing on 

[==========] 158 tests from 15 test cases ran. (280470 ms total)
[  PASSED  ] 156 tests.
[  FAILED  ] 2 tests, listed below:
[  FAILED  ] ObserverListPerfTest/0.MAYBE_NotifyPerformance, where TypeParam = <type>
[  FAILED  ] ObserverListPerfTest/1.MAYBE_NotifyPerformance, where TypeParam = <type>

 2 FAILED TESTS

examples:
https://ci.chromium.org/p/chrome/builders/luci.chrome.ci/mac-10_13_laptop_high_end-perf/1925
https://ci.chromium.org/p/chrome/builders/luci.chrome.ci/mac-10_13_laptop_high_end-perf/1945

Before that it was passing:

[----------] Global test environment tear-down
[==========] 158 tests from 15 test cases ran. (292072 ms total)
[  PASSED  ] 158 tests.

example: https://ci.chromium.org/p/chrome/builders/luci.chrome.ci/mac-10_13_laptop_high_end-perf/1924

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/13e35fd4140000

Running a functional bisection from 610584 to 610633 to figure out the root cause of this regression.

This could be related to  issue 906686 .

From https://chromium.googlesource.com/chromium/src/+/HEAD/base/README.md#performance-testing
it looks like 

ObserverListPerfTest: Exercises adding, removing and signalling observers.

😿 Pinpoint job stopped with an error.
https://pinpoint-dot-chromeperf.appspot.com/job/13e35fd4140000

All of the runs failed. The most common error (1/20 runs) was:
IOError: [Errno 2] No such file or directory: '/b/s/w/itXzRmPv/tmpC5mBqRtelemetry/histograms.json'

Filed  issue 908505 : Pinpoint job isn't working. I will try to get traction over there.

I guess the only thing to do here now is to disable the test. Can either of the cc'd benchmark owners handle this for me please?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/158390508c619b9c04a79ec3868be57eff702d12

commit 158390508c619b9c04a79ec3868be57eff702d12
Author: Caleb Rouleau <crouleau@chromium.org>
Date: Tue Nov 27 23:19:05 2018

[go/perfbot-sheriff][base_perftests] Properly disable NotifyPerformance

This change should be committed right away per go/perfbot-sheriff
since this is failing on the waterfall.

r610618 didn't work since
TYPED_TEST(ObserverListPerfTest, MAYBE_NotifyPerformance) {
is preprocessed to
something_MAYBE_NotifyPerformance
So then the directive
#define MAYBE_NotifyPerformance DISABLED_NotifyPerformance
is not applied.

This will fix both 908490 and 906686.

Bug:  906686 , 908490 
Change-Id: Ib2adc016fbef79bb889a076e452534f893fb09b5
Reviewed-on: https://chromium-review.googlesource.com/c/1352481
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: John Rummell <jrummell@chromium.org>
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611397}
[modify] https://crrev.com/158390508c619b9c04a79ec3868be57eff702d12/base/observer_list_perftest.cc