Findit identified the culprit r569043 with confidence 85.5% in the config "chromium.chromiumos / linux-chromeos-dbg"
based on the flakiness trend:

https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVynwELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCJpY2hyb21pdW0uY2hyb21pdW1vcy9saW51eC1jaHJvbWVvcy1kYmcvNjQwOC9pbnRlcmFjdGl2ZV91aV90ZXN0cy9URzluYVc1RGRYSnpiM0pVWlhOMExrTjFjbk52Y2tocFpHUmxiZz09DAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw

If the culprit above is wrong, please file a bug using this link and hit submit:
https://bugs.chromium.org/p/chromium/issues/entry?status=Unconfirmed&labels=Pri-1,Test-Findit-Wrong&components=Tools%3ETest%3EFindit%3EFlakiness&summary=%5BFindit%5D%20Flake%20Analyzer%20-%20Wrong%20result%20for%20LoginCursorTest.CursorHidden&comment=Link%20to%20Analysis%3A%20https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVynwELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCJpY2hyb21pdW0uY2hyb21pdW1vcy9saW51eC1jaHJvbWVvcy1kYmcvNjQwOC9pbnRlcmFjdGl2ZV91aV90ZXN0cy9URzluYVc1RGRYSnpiM0pVWlhOMExrTjFjbk52Y2tocFpHUmxiZz09DAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw

Automatically posted by the findit-for-me app (https://goo.gl/Ot9f7N).

Assigning to the owner of the culprit CL.

I see that you created a revert here: https://chromium-review.googlesource.com/c/chromium/src/+/1109617, but you didn't CQ it. As a sheriff, I'm taking the liberty to CQ it myself.

Not sure why the test fails and the CL is relevant. The test crashed and here is the stack:
====
[9584:9584:0620/232651.487428:FATAL:web_view_guest.cc(272)] Check failed: site.has_host(). 
#0 0x7fae6151c8bd base::debug::StackTrace::StackTrace()
#1 0x7fae6126c72c base::debug::StackTrace::StackTrace()
#2 0x7fae612d612d logging::LogMessage::~LogMessage()
#3 0x0000014bba77 extensions::WebViewGuest::GetGuestPartitionConfigForSite()
#4 0x0000041c8a80 ChromeContentBrowserClient::GetStoragePartitionConfigForSite()
#5 0x7fae5c02f252 content::BrowserContext::GetStoragePartitionForSite()
#6 0x00000311f945 chromeos::login::SigninPartitionManager::StartSigninSession()
#7 0x000008e2ab15 chromeos::GaiaScreenHandler::LoadGaia()
#8 0x000008e2a9e4 chromeos::GaiaScreenHandler::LoadAuthExtension()
#9 0x000008e38417 chromeos::GaiaScreenHandler::ShowGaiaScreenIfReady()
#10 0x000000a9150f _ZN4base8internal13FunctorTraitsIMN8chromeos17SelectToSpeakTestEFvvEvE6InvokeIS5_RKNS_7WeakPtrIS3_EEJEEEvT_OT0_DpOT1_
#11 0x000001535f9a _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN10extensions19RequirementsCheckerEFvvERKNS_7WeakPtrIS5_EEJEEEvOT_OT0_DpOT1_
#12 0x000008e40410 _ZN4base8internal7InvokerINS0_9BindStateIMN8chromeos17GaiaScreenHandlerEFvvEJNS_7WeakPtrIS4_EEEEEFvvEE7RunImplIRKS6_RKNSt3__15tupleIJS8_EEEJLm0EEEEvOT_OT0_NSF_16integer_sequenceImJXspT1_EEEE
#13 0x000008e403ac _ZN4base8internal7InvokerINS0_9BindStateIMN8chromeos17GaiaScreenHandlerEFvvEJNS_7WeakPtrIS4_EEEEEFvvEE3RunEPNS0_13BindStateBaseE
#14 0x00000073a8ad _ZNKR4base17RepeatingCallbackIFvvEE3RunEv
#15 0x000008e389b4 chromeos::GaiaScreenHandler::OnCookiesCleared()
#16 0x000000ddc42f _ZN4base8internal13FunctorTraitsIMN11google_apis13RequestSenderEFvRKNS_7WeakPtrINS2_29AuthenticatedRequestInterfaceEEEEvE6InvokeISA_RKNS4_IS3_EEJS8_EEEvT_OT0_DpOT1_
#17 0x000001421e55 _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN10extensions9IconImageEFvRKN3gfx12ImageSkiaRepEERKNS_7WeakPtrIS5_EEJS9_EEEvOT_OT0_DpOT1_
#18 0x000008e4001d _ZN4base8internal7InvokerINS0_9BindStateIMN8chromeos17GaiaScreenHandlerEFvRKNS_17RepeatingCallbackIFvvEEEEJNS_7WeakPtrIS4_EES7_EEES6_E7RunImplIRKSB_RKNSt3__15tupleIJSD_S7_EEEJLm0ELm1EEEEvOT_OT0_NSJ_16integer_sequenceImJXspT1_EEEE
#19 0x000008e3ff2c _ZN4base8internal7InvokerINS0_9BindStateIMN8chromeos17GaiaScreenHandlerEFvRKNS_17RepeatingCallbackIFvvEEEEJNS_7WeakPtrIS4_EES7_EEES6_E3RunEPNS0_13BindStateBaseE
#20 0x00000073a8ad _ZNKR4base17RepeatingCallbackIFvvEE3RunEv
#21 0x000003463e35 chromeos::ProfileHelper::OnSigninProfileCleared()
#22 0x000000a9150f _ZN4base8internal13FunctorTraitsIMN8chromeos17SelectToSpeakTestEFvvEvE6InvokeIS5_RKNS_7WeakPtrIS3_EEJEEEvT_OT0_DpOT1_
#23 0x00000346753a _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN8chromeos13ProfileHelperEFvvERKNS_7WeakPtrIS5_EEJEEEvOT_OT0_DpOT1_
#24 0x0000034674d0 _ZN4base8internal7InvokerINS0_9BindStateIMN8chromeos13ProfileHelperEFvvEJNS_7WeakPtrIS4_EEEEEFvvEE7RunImplIRKS6_RKNSt3__15tupleIJS8_EEEJLm0EEEEvOT_OT0_NSF_16integer_sequenceImJXspT1_EEEE
#25 0x00000346741c _ZN4base8internal7InvokerINS0_9BindStateIMN8chromeos13ProfileHelperEFvvEJNS_7WeakPtrIS4_EEEEEFvvEE3RunEPNS0_13BindStateBaseE
#26 0x7fae6121da5e _ZNO4base12OnceCallbackIFvvEE3RunEv
#27 0x7fae6121d3b8 base::(anonymous namespace)::BarrierInfo::Run()
#28 0x7fae6121d6bd _ZN4base8internal13FunctorTraitsIMNS_12_GLOBAL__N_111BarrierInfoEFvvEvE6InvokeIS5_PS3_JEEEvT_OT0_DpOT1_
#29 0x7fae6121d604 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMNS_12_GLOBAL__N_111BarrierInfoEFvvEJPS5_EEEvOT_DpOT0_
#30 0x7fae6121d5b5 _ZN4base8internal7InvokerINS0_9BindStateIMNS_12_GLOBAL__N_111BarrierInfoEFvvEJNS0_12OwnedWrapperIS4_EEEEEFvvEE7RunImplIRKS6_RKNSt3__15tupleIJS8_EEEJLm0EEEEvOT_OT0_NSF_16integer_sequenceImJXspT1_EEEE
#31 0x7fae6121d4fc _ZN4base8internal7InvokerINS0_9BindStateIMNS_12_GLOBAL__N_111BarrierInfoEFvvEJNS0_12OwnedWrapperIS4_EEEEEFvvEE3RunEPNS0_13BindStateBaseE
#32 0x00000073a8ad _ZNKR4base17RepeatingCallbackIFvvEE3RunEv
#33 0x00000346494c chromeos::ProfileHelper::OnBrowsingDataRemoverDone()
#34 0x7fae5c075087 content::BrowsingDataRemoverImpl::Notify()
#35 0x7fae5c07545a content::BrowsingDataRemoverImpl::OnTaskComplete()
#36 0x7fae5add9abf _ZN4base8internal13FunctorTraitsIMN7content15ChildThreadImplEFvvEvE6InvokeIS5_NS_7WeakPtrIS3_EEJEEEvT_OT0_DpOT1_
#37 0x7fae5c077fca _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIMN7content23BrowsingDataRemoverImplEFvvENS_7WeakPtrIS5_EEJEEEvOT_OT0_DpOT1_
#38 0x7fae5c077f60 _ZN4base8internal7InvokerINS0_9BindStateIMN7content23BrowsingDataRemoverImplEFvvEJNS_7WeakPtrIS4_EEEEEFvvEE7RunImplIS6_NSt3__15tupleIJS8_EEEJLm0EEEEvOT_OT0_NSD_16integer_sequenceImJXspT1_EEEE
#39 0x7fae5c077eb9 _ZN4base8internal7InvokerINS0_9BindStateIMN7content23BrowsingDataRemoverImplEFvvEJNS_7WeakPtrIS4_EEEEEFvvEE7RunOnceEPNS0_13BindStateBaseE
#40 0x000000ac076e _ZNO4base12OnceCallbackIFvvEE3RunEv
#41 0x0000048ff1e3 ChromeBrowsingDataRemoverDelegate::OnTaskComplete()
#42 0x000000a9150f _ZN4base8internal13FunctorTraitsIMN8chromeos17SelectToSpeakTestEFvvEvE6InvokeIS5_RKNS_7WeakPtrIS3_EEJEEEvT_OT0_DpOT1_
#43 0x000001535f9a _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN10extensions19RequirementsCheckerEFvvERKNS_7WeakPtrIS5_EEJEEEvOT_OT0_DpOT1_
#44 0x000004903bd0 _ZN4base8internal7InvokerINS0_9BindStateIM33ChromeBrowsingDataRemoverDelegateFvvEJNS_7WeakPtrIS3_EEEEEFvvEE7RunImplIS5_NSt3__15tupleIJS7_EEEJLm0EEEEvOT_OT0_NSC_16integer_sequenceImJXspT1_EEEE
#45 0x000004903b29 _ZN4base8internal7InvokerINS0_9BindStateIM33ChromeBrowsingDataRemoverDelegateFvvEJNS_7WeakPtrIS3_EEEEEFvvEE7RunOnceEPNS0_13BindStateBaseE
#46 0x000000ac076e _ZNO4base12OnceCallbackIFvvEE3RunEv
#47 0x0000048fe40f (anonymous namespace)::OnClearedCookies()
#48 0x0000049021c4 _ZN4base8internal13FunctorTraitsIPFvNS_12OnceCallbackIFvvEEEN4mojo12InterfacePtrIN7network5mojom13CookieManagerEEEjEvE6InvokeISC_JS4_SA_jEEEvOT_DpOT0_
#49 0x00000490213d _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIPFvNS_12OnceCallbackIFvvEEEN4mojo12InterfacePtrIN7network5mojom13CookieManagerEEEjEJS6_SC_jEEEvOT_DpOT0_
#50 0x0000049020dd _ZN4base8internal7InvokerINS0_9BindStateIPFvNS_12OnceCallbackIFvvEEEN4mojo12InterfacePtrIN7network5mojom13CookieManagerEEEjEJS5_SB_EEEFvjEE7RunImplISD_NSt3__15tupleIJS5_SB_EEEJLm0ELm1EEEEvOT_OT0_NSI_16integer_sequenceImJXspT1_EEEEOj
#51 0x000004901fe8 _ZN4base8internal7InvokerINS0_9BindStateIPFvNS_12OnceCallbackIFvvEEEN4mojo12InterfacePtrIN7network5mojom13CookieManagerEEEjEJS5_SB_EEEFvjEE7RunOnceEPNS0_13BindStateBaseEj
#52 0x000000c9d6ff _ZNO4base12OnceCallbackIFvNS_4File5ErrorEEE3RunES2_
#53 0x000000e4fa3a network::mojom::CookieManager_DeleteCookies_ForwardToCallback::Accept()
#54 0x7fae60767c4a mojo::InterfaceEndpointClient::HandleValidatedMessage()
#55 0x7fae60766871 mojo::InterfaceEndpointClient::HandleIncomingMessageThunk::Accept()
#56 0x7fae60764d28 mojo::FilterChain::Accept()
#57 0x7fae6076a746 mojo::InterfaceEndpointClient::HandleIncomingMessage()
#58 0x7fae60776b62 mojo::internal::MultiplexRouter::ProcessIncomingMessage()
#59 0x7fae60776185 mojo::internal::MultiplexRouter::Accept()
#60 0x7fae60764d28 mojo::FilterChain::Accept()
#61 0x7fae60757962 mojo::Connector::ReadSingleMessage()

 Issue 855080  has been merged into this issue.

Detected 3 new flakes for test/step "LoginCursorTest.CursorHidden". To see the actual flakes, please visit https://chromium-try-flakes.appspot.com/all_flake_occurrences?key=ahVzfmNocm9taXVtLXRyeS1mbGFrZXNyJwsSBUZsYWtlIhxMb2dpbkN1cnNvclRlc3QuQ3Vyc29ySGlkZGVuDA. This message was posted automatically by the chromium-try-flakes app. Since flakiness is ongoing, the issue was moved back into Sheriff Bug Queue (unless already there).

Findit identified the culprit r570105 with confidence 95.2% in the config "tryserver.chromium.chromiumos / linux-chromeos-rel"
based on the flakiness trend:

https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVynwELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCJpY2hyb21pdW0uY2hyb21pdW1vcy9saW51eC1jaHJvbWVvcy1yZWwvOTg0NC9pbnRlcmFjdGl2ZV91aV90ZXN0cy9URzluYVc1RGRYSnpiM0pVWlhOMExrTjFjbk52Y2tocFpHUmxiZz09DAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw

If the culprit above is wrong, please file a bug using this link and hit submit:
https://bugs.chromium.org/p/chromium/issues/entry?status=Unconfirmed&labels=Pri-1,Test-Findit-Wrong&components=Tools%3ETest%3EFindit%3EFlakiness&summary=%5BFindit%5D%20Flake%20Analyzer%20-%20Wrong%20result%20for%20LoginCursorTest.CursorHidden&comment=Link%20to%20Analysis%3A%20https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVynwELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCJpY2hyb21pdW0uY2hyb21pdW1vcy9saW51eC1jaHJvbWVvcy1yZWwvOTg0NC9pbnRlcmFjdGl2ZV91aV90ZXN0cy9URzluYVc1RGRYSnpiM0pVWlhOMExrTjFjbk52Y2tocFpHUmxiZz09DAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw

Automatically posted by the findit-for-me app (https://goo.gl/Ot9f7N).

Findit identified the culprit r570105 with confidence 73.0% in the config "chromium.chromiumos / linux-chromeos-rel"
based on the flakiness trend:

https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVynwELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCJpY2hyb21pdW0uY2hyb21pdW1vcy9saW51eC1jaHJvbWVvcy1yZWwvOTg0Ny9pbnRlcmFjdGl2ZV91aV90ZXN0cy9URzluYVc1RGRYSnpiM0pVWlhOMExrTjFjbk52Y2tocFpHUmxiZz09DAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw

If the culprit above is wrong, please file a bug using this link and hit submit:
https://bugs.chromium.org/p/chromium/issues/entry?status=Unconfirmed&labels=Pri-1,Test-Findit-Wrong&components=Tools%3ETest%3EFindit%3EFlakiness&summary=%5BFindit%5D%20Flake%20Analyzer%20-%20Wrong%20result%20for%20LoginCursorTest.CursorHidden&comment=Link%20to%20Analysis%3A%20https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVynwELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCJpY2hyb21pdW0uY2hyb21pdW1vcy9saW51eC1jaHJvbWVvcy1yZWwvOTg0Ny9pbnRlcmFjdGl2ZV91aV90ZXN0cy9URzluYVc1RGRYSnpiM0pVWlhOMExrTjFjbk52Y2tocFpHUmxiZz09DAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw

Automatically posted by the findit-for-me app (https://goo.gl/Ot9f7N).

Marking as fixed since the breaking change was reverted.