ChromeVoxLiveRegionsUnitTest.ProgressBarLiveRegionEvents
ChromeVoxLiveRegionsUnitTest.RevealAlertLiveRegion

appear to be flaky.

First failure: https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/linux-chromeos-rel/16517

Failure:

[1272:1272:1126/142539.336816:ERROR:web_ui_test_handler.cc(100)] Failed: RUN_TEST_F("ChromeVoxLiveRegionsUnitTest","ProgressBarLiveRegionEvents")
AssertionError: expected undefined to equal 'Progress bar 2'
    at Function.assert.strictEqual (file:///b/s/w/ir/third_party/chaijs/chai.js:2277:32)
    at assertEquals (file:///b/s/w/ir/chrome/test/data/webui/test_api.js:923:15)
    at ChromeVoxLiveRegionsUnitTest.<anonymous> (file:///b/s/w/ir/out/Release/test_data/chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_test.unitjs:204:5)
    at ChromeVoxLiveRegionsUnitTest.<anonymous> (file:///b/s/w/ir/chrome/browser/resources/chromeos/chromevox/testing/chromevox_unittest_base.js:123:12)
    at CallbackHelper.<anonymous> (file:///b/s/w/ir/chrome/browser/resources/chromeos/chromevox/testing/callback_helper.js:32:16)
    at CallFunctionAction.invoke (file:///b/s/w/ir/chrome/test/data/webui/test_api.js:1430:22)
    at RunAllAction.invoke (file:///b/s/w/ir/chrome/test/data/webui/test_api.js:1591:35)
    at file:///b/s/w/ir/chrome/browser/resources/chromeos/chromevox/testing/callback_helper.js:42:14
    at file:///b/s/w/ir/chrome/browser/resources/chromeos/chromevox/chromevox/injected/event_watcher.js:319:59
gen/chrome/browser/resources/chromeos/chromevox/chromevox/injected/live_regions_test-gen.cc:1920: Failure
Value of: RunJavascriptTestF( true, "ChromeVoxLiveRegionsUnitTest", "ProgressBarLiveRegionEvents")
  Actual: false
Expected: true
Stack trace:
#0 0x563d88a0121c testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#1 0x563d88a00bf9 testing::internal::AssertHelper::operator=()
#2 0x563d8aa99e6a ChromeVoxLiveRegionsUnitTest_ProgressBarLiveRegionEvents_Test::RunTestOnMainThread()
#3 0x563d8b10cead content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#4 0x563d8acce615 ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#5 0x563d8accd5b2 ChromeBrowserMainParts::PreMainMessageLoopRun()
#6 0x563d8858b412 chromeos::ChromeBrowserMainPartsChromeos::PreMainMessageLoopRun()
#7 0x563d8959c0b5 content::BrowserMainLoop::PreMainMessageLoopRun()
#8 0x563d8992af07 content::StartupTaskRunner::RunAllTasksNow()
#9 0x563d8959aec0 content::BrowserMainLoop::CreateStartupTasks()
#10 0x563d8959e038 content::BrowserMainRunnerImpl::Initialize()
#11 0x563d895992c2 content::BrowserMain()
#12 0x563d8a81a139 content::ContentMainRunnerImpl::Run()
#13 0x563d8c90fbdc service_manager::Main()
#14 0x563d8a818614 content::ContentMain()
#15 0x563d8b10cae1 content::BrowserTestBase::SetUp()
#16 0x563d8ac7e1a4 InProcessBrowserTest::SetUp()

That is, we expect `assertEquals('Progress bar 2', utterances[utterances.length - 1]);` but the last element of `utterances` turned out to be null...

Probably duplicate of  Issue 908652 . Revert is on its way.
https://chromium-review.googlesource.com/c/chromium/src/+/1351898

Revert landed (Scott beat me to it)
https://chromium-review.googlesource.com/c/chromium/src/+/1351808

Bots are green :) Thanks!