When enabling Dice M3, all these tests fail

To repro: enable Dice M3 in filedtrial_testing_config, like:
https://chromium-review.googlesource.com/c/chromium/src/+/1071289


Test output is similar to this:


[234801:234809:0524/150631.296214:ERROR:instance.cc(49)] Unable to locate service manifest for ui
[234801:234809:0524/150631.296339:ERROR:service_manager.cc(942)] Failed to resolve service name: ui
[234801:234801:0524/150631.373838:WARNING:password_store_factory.cc(250)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
[234801:234801:0524/150631.591954:WARNING:gaia_auth_fetcher.cc(902)] Could not reach Google Accounts servers: errno -11
[234801:234801:0524/150632.593599:WARNING:gaia_auth_fetcher.cc(902)] Could not reach Google Accounts servers: errno -11
[234801:234801:0524/150633.408993:INFO:CONSOLE(1236)] "Running TestCase SettingsA11ySignOut.SIGN_OUT_accesskeys", source: file:///usr/local/google/home/droger/dev/chromium/src/chrome/test/data/webui/test_api.js (1236)
[234801:234801:0524/150634.275191:WARNING:CONSOLE(24)] "Error: Assertion failed
    at assert (chrome://settings/crisper.js:24:144)
    at Accessible Dialog.browserProxy.getSyncStatus.then (file:///usr/local/google/home/droger/dev/chromium/src/out/Release/test_data/chrome/test/data/webui/settings/a11y/sign_out_a11y_test.js:72:9)", source: chrome://settings/crisper.js (24)
[234801:234801:0524/150634.276608:ERROR:CONSOLE(48)] "Mocha test failed: SIGN_OUT_accesskeys Accessible Dialog
Error: Assertion failed
    at assert (crisper.js:24:144)
    at Accessible Dialog.browserProxy.getSyncStatus.then (file:///usr/local/google/home/droger/dev/chromium/src/out/Release/test_data/chrome/test/data/webui/settings/a11y/sign_out_a11y_test.js:72:9)
", source: file:///usr/local/google/home/droger/dev/chromium/src/chrome/test/data/webui/mocha_adapter.js (48)
[234801:234801:0524/150634.498306:ERROR:web_ui_test_handler.cc(100)] Test Errors: 1/1 tests had failed assertions.
[234801:234801:0524/150634.498527:ERROR:web_ui_browser_test.cc(474)] CONDITION FAILURE: encountered javascript console error(s):
[234801:234801:0524/150634.498553:ERROR:web_ui_browser_test.cc(476)] JS ERROR: '[234801:234801:0524/150634.276608:ERROR:CONSOLE(48)] "Mocha test failed: SIGN_OUT_accesskeys Accessible Dialog
Error: Assertion failed
    at assert (crisper.js:24:144)
    at Accessible Dialog.browserProxy.getSyncStatus.then (file:///usr/local/google/home/droger/dev/chromium/src/out/Release/test_data/chrome/test/data/webui/settings/a11y/sign_out_a11y_test.js:72:9)
", source: file:///usr/local/google/home/droger/dev/chromium/src/chrome/test/data/webui/mocha_adapter.js (48)
'
[234801:234801:0524/150634.498583:ERROR:web_ui_browser_test.cc(478)] JS call assumed failed, because JS console error(s) found.
gen/chrome/test/data/webui/settings/a11y/sign_out_a11y_test-gen.cc:51: Failure
Value of: RunJavascriptTestF( true, "SettingsA11ySignOut", "SIGN_OUT_accesskeys")
  Actual: false
Expected: true
Stack trace:
#0 0x0000026149cc testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#1 0x0000026143a9 testing::internal::AssertHelper::operator=()
#2 0x000002553b78 SettingsA11ySignOut_SIGN_OUT_accesskeys_Test::RunTestOnMainThread()
#3 0x0000031887fe content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#4 0x000002c5edfa ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#5 0x000002c5db9a ChromeBrowserMainParts::PreMainMessageLoopRun()
#6 0x7f649a03e031 content::BrowserMainLoop::PreMainMessageLoopRun()
#7 0x7f649a529035 content::StartupTaskRunner::RunAllTasksNow()
#8 0x7f649a03ca9c content::BrowserMainLoop::CreateStartupTasks()
#9 0x7f649a040dc5 content::BrowserMainRunnerImpl::Initialize()
#10 0x7f649a03a4b5 content::BrowserMain()
#11 0x7f649aaeed2a content::RunBrowserProcessMain()
#12 0x7f649aaefda4 content::ContentMainRunnerImpl::Run()
#13 0x7f64980d76bf service_manager::Main()
#14 0x7f649aaedb94 content::ContentMain()
#15 0x000003188362 content::BrowserTestBase::SetUp()
#16 0x000002bf6300 InProcessBrowserTest::SetUp()

[234801:234809:0524/150634.696095:WARNING:discardable_shared_memory_manager.cc(431)] Some MojoDiscardableSharedMemoryManagerImpls are still alive. They will be leaked.
[234801:234801:0524/150634.698472:WARNING:url_request_context_getter.cc(43)] URLRequestContextGetter leaking due to no owning thread.
[234801:234801:0524/150634.700565:WARNING:pref_notifier_impl.cc(23)] Pref observer found at shutdown.
[234801:234801:0524/150634.700613:WARNING:pref_notifier_impl.cc(23)] Pref observer found at shutdown.
[234801:234987:0524/150634.706004:WARNING:internal_linux.cc(64)] Failed to read /proc/234833/stat