A series of viz_browsertests have begun failing after: https://chromium-review.googlesource.com/c/chromium/src/+/938678

They are attempting to serialize an empty unguessable token during eviction.

FATAL:unguessable_token.h(58)] Check failed: !is_empty().
base::debug::StackTrace::StackTrace()
logging::LogMessage::~LogMessage()
mojo::internal::Serializer<>::Serialize()
mojo::internal::Serializer<>::Serialize()
mojo::internal::Serializer<>::Serialize()
mojo::internal::ArraySerializer<>::SerializeElements()
mojo::internal::Serializer<>::Serialize()
viz::mojom::FrameSinkManagerProxy::EvictSurfaces()
content::DelegatedFrameHost::EvictDelegatedFrame()
viz::FrameEvictionManager::CullUnlockedFrames()
content::DelegatedFrameHost::OnFirstSurfaceActivation()
viz::mojom::FrameSinkManagerClientStubDispatch::Accept()
mojo::InterfaceEndpointClient::HandleValidatedMessage()
mojo::FilterChain::Accept()
mojo::InterfaceEndpointClient::HandleIncomingMessage()
mojo::internal::MultiplexRouter::ProcessIncomingMessage()
mojo::internal::MultiplexRouter::Accept()
mojo::FilterChain::Accept()
mojo::Connector::ReadSingleMessage()
mojo::Connector::ReadAllAvailableMessages()
mojo::Connector::OnHandleReadyInternal()
content::(anonymous namespace)::InitializeErrorCallback()
mojo::SimpleWatcher::OnHandleReady()
..... Task looping

Example logs:
https://logs.chromium.org/v/?s=chromium%2Fbb%2Fchromium.fyi%2FLinux_Viz%2F2606%2F%2B%2Frecipes%2Fsteps%2Fviz_browser_tests%2F0%2Flogs%2FTaskManagerViewTest.SelectionConsistency%2F0

Example failed build:
https://ci.chromium.org/buildbot/chromium.fyi/Linux%20Viz/2606

Failing tests:
TaskManagerViewTest.SelectionConsistency
CaptivePortalBrowserTest.LoginExtraNavigations
ProcessManagementTest.ProcessOverflow
WindowOpenApiTest.PopupBlockingExtension
ServiceWorkerTestWithNativeBindings/ServiceWorkerTest.BackgroundPageIsWokenIfAsleep/0
BrowserTest.WindowOpenClose1
ServiceWorkerTestWithJSBindings/ServiceWorkerTest.BackgroundPageIsWokenIfAsleep/0
ContextMenuBrowserTest.OpenLinkInProfile
CaptivePortalBrowserTest.NavigateBrokenTab
CaptivePortalBrowserTest.CloseLoginTab
ServiceWorkerTestWithNativeBindings/ServiceWorkerTest.FetchArbitraryPaths/0
ServiceWorkerTestWithJSBindings/ServiceWorkerTest.FetchArbitraryPaths/0
PermissionRequestManagerBrowserTest.BackgroundTabNavigation