Below mentioned content_browsertests fails in Win, Linux and Mac official.desktop builder.

NetInternalsTest.netInternalsDomainSecurityPolicyViewExpectCTAddDelete
NetInternalsTest.netInternalsDomainSecurityPolicyViewExpectCTAddTwice
NetInternalsTest.netInternalsDomainSecurityPolicyViewExpectCTAddOverwrite

Link to the Builder
===================
https://uberchromegw.corp.google.com/i/official.desktop/builders/linux64/builds/521

Link to the log file
====================
https://uberchromegw.corp.google.com/i/official.desktop/builders/linux64/builds/521/steps/browser_tests/logs/stdio

Error Log
=========
459:459:0817/223727.645197:ERROR:web_ui_test_handler.cc(82)] Failed: RUN_TEST_F("NetInternalsTest","netInternalsDomainSecurityPolicyViewExpectCTAddDelete")
AssertionError: expected 0 to equal 1
    at Function.assert.strictEqual (chai.js:2277:32)
    at assertEquals (test_api.js:892:17)
    at test_api.js:1019:20
    at AddExpectCTTask.checkNotFound_ (domain_security_policy_view.js:96:5)
    at AddExpectCTTask.onQueryResult_ (domain_security_policy_view.js:71:12)
    at AddExpectCTTask.onExpectCTQueryResult (domain_security_policy_view.js:349:10)
    at BrowserBridge.receivedExpectCTResult (chrome://net-internals/index.js:2071:36)
    at BrowserBridge.receive (chrome://net-internals/index.js:1991:20)
    at CallFunctionAction.invoke (test_api.js:1369:24)
    at RunAllAction.invoke (test_api.js:1530:37)
gen/chrome/test/data/webui/net_internals/domain_security_policy_view-gen.cc:230: Failure
Value of: RunJavascriptTestF( true, "NetInternalsTest", "netInternalsDomainSecurityPolicyViewExpectCTAddDelete")
  Actual: false
Expected: true
[459:459:0817/223727.660677:WARNING:browser_main_loop.cc(287)] <unknown>: AT-SPI: Could not obtain desktop path or name

[459:459:0817/223727.661615:WARNING:browser_main_loop.cc(287)] <unknown>: AT-SPI: Could not obtain desktop path or name

[  FAILED  ] NetInternalsTest.netInternalsDomainSecurityPolicyViewExpectCTAddDelete, where TypeParam =  and GetParam() =  (1752 ms)
[4783/6739] NetInternalsTest.netInternalsDomainSecurityPolicyViewExpectCTAddDelete (2097 ms)
[4784/6739] NetInternalsTest.netInternalsDomainSecurityPolicyViewExpectCTAddFail (2097 ms)
[4785/6739] NetInternalsTest.netInternalsDomainSecurityPolicyViewExpectCTAddError (2095 ms)
[4786/6739] NetInternalsTest.netInternalsLogUtilExportImport (2097 ms)
[4787/6739] NetInternalsTest.netInternalsLogUtilImportNetLogFile (2095 ms)
[ RUN      ] NetInternalsTest.netInternalsDomainSecurityPolicyViewExpectCTAddOverwrite
Xlib:  extension "RANDR" missing on display ":9".

Regression Information
======================
First Bad Build: https://uberchromegw.corp.google.com/i/official.desktop/builders/mac64/builds/2100
Last Good Build: https://uberchromegw.corp.google.com/i/official.desktop/builders/mac64/builds/2099

Flaky Information 
=================
Flaky Information
Build ranges checked for flakiness: 472 : 521
Number of times failed: 1 times out of 48 builds.

Possible suspect
================
https://chromium.googlesource.com/chromium/src/+/702a54b13c210e480cb1729adee4f8dfcd136bd0

Emily, seems like you made some recent code change.Would you mind taking a look at the failure. 
We are trying to make the builder green, so it would be great to have a fix soon.