Central as Beta simulation: https://treeherder.mozilla.org/#/jobs?repo=try&group_state=expanded&selectedJob=275047742&resultStatus=success%2Ctestfailed%2Cbusted%2Cexception&revision=79a10eb84e707f42814b4ac803be9bdc535a14f2&searchStr=%28dt

Failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=275047742&repo=try&lineNumber=29596

[task 2019-11-07T11:59:59.652Z] 11:59:59 INFO - TEST-START | devtools/client/debugger/test/mochitest/browser_dbg-windowless-service-workers.js
[task 2019-11-07T11:59:59.711Z] 11:59:59 INFO - GECKO(9640) | ++DOCSHELL 000001E3E0053000 == 2 [pid = 1856] [id = {bd31e68c-1821-4fc9-a6c5-4f557601a153}]
[task 2019-11-07T11:59:59.711Z] 11:59:59 INFO - GECKO(9640) | ++DOMWINDOW == 3 (000001E3E00AB200) [pid = 1856] [serial = 286] [outer = 0000000000000000]
[task 2019-11-07T11:59:59.711Z] 11:59:59 INFO - GECKO(9640) | ++DOMWINDOW == 4 (000001E3E00D0000) [pid = 1856] [serial = 287] [outer = 000001E3E00AB200]
[task 2019-11-07T11:59:59.790Z] 11:59:59 INFO - GECKO(9640) | ++DOMWINDOW == 5 (000001E3E6450000) [pid = 1856] [serial = 288] [outer = 000001E3E00AB200]
[task 2019-11-07T11:59:59.890Z] 11:59:59 INFO - GECKO(9640) | ++DOCSHELL 000001DB5C2DC000 == 7 [pid = 7420] [id = {99fbb437-d672-47b4-aaf1-1d41665bdc93}]
[task 2019-11-07T11:59:59.890Z] 11:59:59 INFO - GECKO(9640) | ++DOMWINDOW == 19 (000001DB5B59AC40) [pid = 7420] [serial = 743] [outer = 0000000000000000]
[task 2019-11-07T11:59:59.890Z] 11:59:59 INFO - GECKO(9640) | ++DOMWINDOW == 20 (000001DB5D15C800) [pid = 7420] [serial = 744] [outer = 000001DB5B59AC40]
[task 2019-11-07T11:59:59.916Z] 11:59:59 INFO - GECKO(9640) | ++DOMWINDOW == 21 (000001DB5FCAAC00) [pid = 7420] [serial = 745] [outer = 000001DB5B59AC40]
[task 2019-11-07T11:59:59.955Z] 11:59:59 INFO - GECKO(9640) | ++DOMWINDOW == 22 (000001DB60B89400) [pid = 7420] [serial = 746] [outer = 000001DB5B59AC40]
[task 2019-11-07T12:00:00.058Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: NS_ENSURE_SUCCESS(rv, rv) failed with result 0x80004005: file z:/build/build/src/dom/base/nsContentUtils.cpp, line 3719
[task 2019-11-07T12:00:00.184Z] 12:00:00 INFO - GECKO(9640) | ++DOCSHELL 000001DB5BBE3000 == 8 [pid = 7420] [id = {c32f6b9a-61a5-4834-86f6-54734860839e}]
[task 2019-11-07T12:00:00.184Z] 12:00:00 INFO - GECKO(9640) | ++DOMWINDOW == 23 (000001DB5BBB6200) [pid = 7420] [serial = 747] [outer = 0000000000000000]
[task 2019-11-07T12:00:00.184Z] 12:00:00 INFO - GECKO(9640) | ++DOMWINDOW == 24 (000001DB60B83C00) [pid = 7420] [serial = 748] [outer = 000001DB5BBB6200]
[task 2019-11-07T12:00:00.535Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: NS_ENSURE_SUCCESS(rv, nullptr) failed with result 0x804B000A: file z:/build/build/src/extensions/permissions/nsPermission.cpp, line 45
[task 2019-11-07T12:00:00.535Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: '!principal', file z:/build/build/src/netwerk/cookie/CookieSettings.cpp, line 132
[task 2019-11-07T12:00:00.535Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: 'NS_FAILED(rv)', file z:/build/build/src/toolkit/components/antitracking/StorageAccess.cpp, line 33
[task 2019-11-07T12:00:00.537Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: NS_ENSURE_SUCCESS(rv, nullptr) failed with result 0x804B000A: file z:/build/build/src/extensions/permissions/nsPermission.cpp, line 45
[task 2019-11-07T12:00:00.537Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: '!principal', file z:/build/build/src/netwerk/cookie/CookieSettings.cpp, line 132
[task 2019-11-07T12:00:00.537Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: 'NS_FAILED(rv)', file z:/build/build/src/toolkit/components/antitracking/StorageAccess.cpp, line 33
[task 2019-11-07T12:00:00.839Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: NS_ENSURE_SUCCESS(rv, nullptr) failed with result 0x804B000A: file z:/build/build/src/extensions/permissions/nsPermission.cpp, line 45
[task 2019-11-07T12:00:00.839Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: '!principal', file z:/build/build/src/netwerk/cookie/CookieSettings.cpp, line 132
[task 2019-11-07T12:00:00.839Z] 12:00:00 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: 'NS_FAILED(rv)', file z:/build/build/src/toolkit/components/antitracking/StorageAccess.cpp, line 33
[task 2019-11-07T12:00:00.978Z] 12:00:00 INFO - GECKO(9640) | [ACTION] SET_ORIENTATION - {"type":"SET_ORIENTATION","orientation":"horizontal"}
[task 2019-11-07T12:00:01.036Z] 12:00:01 INFO - GECKO(9640) | [ACTION] UPDATE_EVENT_LISTENERS - {"type":"UPDATE_EVENT_LISTENERS","active":[]}
[task 2019-11-07T12:00:01.066Z] 12:00:01 INFO - GECKO(9640) | [ACTION] RECEIVE_EVENT_LISTENER_TYPES - {"type":"RECEIVE_EVENT_LISTENER_TYPES","categories":[{"name":"Animation","events":[{"id":"animationframe.request","name":"Request Animation Frame"},{"id":"animationframe.cancel","name":"Cancel Animation Frame"},{"id":"animationframe.fire","name":"Animation Frame fired"}]},{"name":"Clipboard","events":[{"id":"event.clipboard.copy","name":"copy"},{"id":"event.clipboard.cut","name":"cut"},{"id":"event.clipboard.paste","name":"paste"},{"id":"event.clipboard.beforecopy","name":"beforecopy"},{"id":"event.clipboard.beforecut","name":"beforecut"},{"id":"event.clipboard.beforepaste","name":"beforepaste"}]},{"name":"Control","events":[{"id":"event.control.resize","name":"resize"},{"id":"event.control.scroll","name":"scroll"},{"id":"event.control.zoom","name":"zoom"},{"id":"event.control.focus","name":"focus"},{"id":"event.control.blur","name":"blur"},{"id":"event.control.select","name":"select"},{"id":"event.control.change","name":"change"},{"id":"event.control.submit","name":"submit"},{"id":"event.control.reset","name":"reset"}]},{"name":"DOM Mutation","events":[{"id":"event.dom-mutation.DOMActivate","name":"DOMActivate"},{"id":"event.dom-mutation.DOMFocusIn","name":"DOMFocusIn"},{"id":"event.dom-mutation.DOMFocusOut","name":"DOMFocusOut"},{"id":"event.dom-mutation.DOMAttrModified","name":"DOMAttrModified"},{"id":"event.dom-mutation.DOMCharacterDataModified","name":"DOMCharacterDataModified"},{"id":"event.dom-mutation.DOMNodeInserted","name":"DOMNodeInserted"},{"id":"event.dom-mutation.DOMNodeInsertedIntoDocument","name":"DOMNodeInsertedIntoDocument"},{"id":"event.dom-mutation.DOMNodeRemoved","name":"DOMNodeRemoved"},{"id":"event.dom-mutation.DOMNodeRemovedIntoDocument","name":"DOMNodeRemovedIntoDocument"},{"id":"event.dom-mutation.DOMSubtreeModified","name":"DOMSubtreeModified"},{"id":"event.dom-mutation.DOMContentLoaded","name":"DOMContentLoaded"}]},{"name":"Device","events":[{"id":"event.device.deviceorientation","name":"deviceorientation"},{"id":"event.device.devicemotion","name":"devicemotion"}]},{"name":"Drag and Drop","events":[{"id":"event.drag-and-drop.drag","name":"drag"},{"id":"event.drag-and-drop.dragstart","name":"dragstart"},{"id":"event.drag-and-drop.dragend","name":"dragend"},{"id":"event.drag-and-drop.dragenter","name":"dragenter"},{"id":"event.drag-and-drop.dragover","name":"dragover"},{"id":"event.drag-and-drop.dragleave","name":"dragleave"},{"id":"event.drag-and-drop.drop","name":"drop"}]},{"name":"Keyboard","events":[{"id":"event.keyboard.keydown","name":"keydown"},{"id":"event.keyboard.keyup","name":"keyup"},{"id":"event.keyboard.keypress","name":"keypress"},{"id":"event.keyboard.input","name":"input"}]},{"name":"Load","events":[{"id":"event.load.load","name":"load"},{"id":"event.load.abort","name":"abort"},{"id":"event.load.error","name":"error"},{"id":"event.load.hashchange","name":"hashchange"},{"id":"event.load.popstate","name":"popstate"}]},{"name":"Media","events":[{"id":"event.media.play","name":"play"},{"id":"event.media.pause","name":"pause"},{"id":"event.media.playing","name":"playing"},{"id":"event.media.canplay","name":"canplay"},{"id":"event.media.canplaythrough","name":"canplaythrough"},{"id":"event.media.seeking","name":"seeking"},{"id":"event.media.seeked","name":"seeked"},{"id":"event.media.timeupdate","name":"timeupdate"},{"id":"event.media.ended","name":"ended"},{"id":"event.media.ratechange","name":"ratechange"},{"id":"event.media.durationchange","name":"durationchange"},{"id":"event.media.volumechange","name":"volumechange"},{"id":"event.media.loadstart","name":"loadstart"},{"id":"event.media.progress","name":"progress"},{"id":"event.media.suspend","name":"suspend"},{"id":"event.media.abort","name":"abort"},{"id":"event.media.error","name":"error"},{"id":"event.media.emptied","name":"emptied"},{"id":"event.media.stalled","name":"stalled"},{"id":"event.media.loadedmetadata","name":"loadedmetadata"},{"id":"event.media.loadeddata","name":"loadeddata"},{"id":"event.media.waiting","name":"waiting"}]},{"name":"Mouse","events":[{"id":"event.mouse.auxclick","name":"auxclick"},{"id":"event.mouse.click","name":"click"},{"id":"event.mouse.dblclick","name":"dblclick"},{"id":"event.mouse.mousedown","name":"mousedown"},{"id":"event.mouse.mouseup","name":"mouseup"},{"id":"event.mouse.mouseover","name":"mouseover"},{"id":"event.mouse.mousemove","name":"mousemove"},{"id":"event.mouse.mouseout","name":"mouseout"},{"id":"event.mouse.mouseenter","name":"mouseenter"},{"id":"event.mouse.mouseleave","name":"mouseleave"},{"id":"event.mouse.mousewheel","name":"mousewheel"},{"id":"event.mouse.wheel","name":"wheel"},{"id":"event.mouse.contextmenu","name":"contextmenu"}]},{"name":"Pointer","events":[{"id":"event.pointer.pointerover","name":"pointerover"},{"id":"event.pointer.pointerout","name":"pointerout"},{"id":"event.pointer.pointerenter","name":"pointerenter"},{"id":"event.pointer.pointerleave","name":"pointerleave"},{"id":"event.pointer.pointerdown","name":"pointerdown"},{"id":"event.pointer.pointerup","name":"pointerup"},{"id":"event.pointer.pointermove","name":"pointermove"},{"id":"event.pointer.pointercancel","name":"pointercancel"},{"id":"event.pointer.gotpointercapture","name":"gotpointercapture"},{"id":"event.pointer.lostpointercapture","name":"lostpointercapture"}]},{"name":"Timer","events":[{"id":"timer.timeout.set","name":"setTimeout"},{"id":"timer.timeout.clear","name":"clearTimeout"},{"id":"timer.timeout.fire","name":"setTimeout fired"},{"id":"timer.interval.set","name":"setInterval"},{"id":"timer.interval.clear","name":"clearInterval"},{"id":"timer.interval.fire","name":"setInterval fired"}]},{"name":"Touch","events":[{"id":"event.touch.touchstart","name":"touchstart"},{"id":"event.touch.touchmove","name":"touchmove"},{"id":"event.touch.touchend","name":"touchend"},{"id":"event.touch.touchcancel","name":"touchcancel"}]},{"name":"Worker","events":[{"id":"event.worker.message","name":"message"},{"id":"event.worker.messageerror","name":"messageerror"}]},{"name":"XHR","events":[{"id":"event.xhr.readystatechange","name":"readystatechange"},{"id":"event.xhr.load","name":"load"},{"id":"event.xhr.loadstart","name":"loadstart"},{"id":"event.xhr.loadend","name":"loadend"},{"id":"event.xhr.abort","name":"abort"},{"id":"event.xhr.error","name":"error"},{"id":"event.xhr.progress","name":"progress"},{"id":"event.xhr.timeout","name":"timeout"}]}]}
[task 2019-11-07T12:00:02.640Z] 12:00:02 INFO - GECKO(9640) | [ACTION] CONNECT - {"type":"CONNECT","mainThread":{"url":"http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html","actor":"server0.conn111.child1/thread19","type":"mainThread","name":"Main Thread"},"traits":{"reconfigure":false,"frames":true,"logInPage":true,"canRewind":false,"watchpoints":true},"isWebExtension":false}
[task 2019-11-07T12:00:02.765Z] 12:00:02 INFO - GECKO(9640) | --DOMWINDOW == 7 (000002383D818800) [pid = 10692] [serial = 272] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:02.765Z] 12:00:02 INFO - GECKO(9640) | --DOMWINDOW == 6 (000002383B166C00) [pid = 10692] [serial = 274] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:02.765Z] 12:00:02 INFO - GECKO(9640) | --DOMWINDOW == 5 (000002383D233800) [pid = 10692] [serial = 275] [outer = 0000000000000000] [url = http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-wasm-sourcemaps.html]
[task 2019-11-07T12:00:02.765Z] 12:00:02 INFO - GECKO(9640) | --DOCSHELL 0000023834F42000 == 1 [pid = 10692] [id = {9fb80397-3ec6-46c4-807e-4a21cf9db752}] [url = http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-wasm-sourcemaps.html]
[task 2019-11-07T12:00:02.766Z] 12:00:02 INFO - GECKO(9640) | [ACTION] EVALUATE_EXPRESSIONS - {"type":"EVALUATE_EXPRESSIONS","cx":{"navigateCounter":0,"thread":"server0.conn111.child1/thread19","isPaused":false,"pauseCounter":0},"inputs":[],"results":[]}
[task 2019-11-07T12:00:02.776Z] 12:00:02 INFO - GECKO(9640) | [ACTION] ADD_SOURCES - {"type":"ADD_SOURCES","cx":{"navigateCounter":0},"sources":[{"id":"sourceURL-http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html","url":"http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html","relativeUrl":"http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html","isPrettyPrinted":false,"extensionName":null,"introductionUrl":null,"introductionType":"scriptElement","isBlackBoxed":false,"isWasm":false,"isExtension":false}]}
[task 2019-11-07T12:00:02.786Z] 12:00:02 INFO - GECKO(9640) | [ACTION] INSERT_SOURCE_ACTORS - {"type":"INSERT_SOURCE_ACTORS","items":[{"id":"server0.conn111.child1/source21","actor":"server0.conn111.child1/source21","thread":"server0.conn111.child1/thread19","source":"sourceURL-http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html","isBlackBoxed":false,"sourceMapURL":null,"url":"http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html","introductionUrl":null,"introductionType":"scriptElement"}]}
[task 2019-11-07T12:00:02.804Z] 12:00:02 INFO - GECKO(9640) | [ACTION] SET_EXPANDED_STATE - {"type":"SET_EXPANDED_STATE","expanded":{}}
[task 2019-11-07T12:00:02.809Z] 12:00:02 INFO - GECKO(9640) | [ACTION] SET_EXPANDED_STATE - {"type":"SET_EXPANDED_STATE","expanded":{}}
[task 2019-11-07T12:00:02.879Z] 12:00:02 INFO - GECKO(9640) | [ACTION] ADD_SOURCES - {"type":"ADD_SOURCES","cx":{"navigateCounter":0},"sources":[]}
[task 2019-11-07T12:00:02.879Z] 12:00:02 INFO - GECKO(9640) | [ACTION] INSERT_SOURCE_ACTORS - {"type":"INSERT_SOURCE_ACTORS","items":[]}
[task 2019-11-07T12:00:02.963Z] 12:00:02 INFO - GECKO(9640) | [Child 1856, Main Thread] WARNING: '!window', file z:/build/build/src/dom/cache/CacheStorage.cpp, line 574
[task 2019-11-07T12:00:02.993Z] 12:00:02 INFO - GECKO(9640) | [Child 1856, Main Thread] WARNING: Workers don't support the 'mem.mem.' preference!: file z:/build/build/src/dom/workers/RuntimeService.cpp, line 547
[task 2019-11-07T12:00:02.993Z] 12:00:02 INFO - GECKO(9640) | [Child 1856, Main Thread] WARNING: '!window', file z:/build/build/src/dom/cache/CacheStorage.cpp, line 574
[task 2019-11-07T12:00:03.033Z] 12:00:03 INFO - GECKO(9640) | Starting
[task 2019-11-07T12:00:03.033Z] 12:00:03 INFO - GECKO(9640) | Registered, scope is: http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html
[task 2019-11-07T12:00:03.033Z] 12:00:03 INFO - GECKO(9640) | Activate
[task 2019-11-07T12:00:03.143Z] 12:00:03 INFO - GECKO(9640) | console.error: "Error writing response to: listWorkers"
[task 2019-11-07T12:00:03.143Z] 12:00:03 INFO - GECKO(9640) | console.error: "Error while calling actor 'contentProcessTarget's method 'listWorkers'" "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIServiceWorkerManager.getRegistrationByPrincipal]"
[task 2019-11-07T12:00:03.143Z] 12:00:03 INFO - GECKO(9640) | console.error: "_getServiceWorkerRegistrationInfo@resource://devtools/server/actors/targets/worker.js:170:16\nform@resource://devtools/server/actors/targets/worker.js:65:35\nwrite@resource://devtools/shared/protocol/types.js:363:32\ntypes.addArrayType/write/<@resource://devtools/shared/protocol/types.js:220:33\nwrite@resource://devtools/shared/protocol/types.js:220:16\nwrite@resource://devtools/shared/protocol/types.js:387:22\nwrite@resource://devtools/shared/protocol/types.js:268:39\nwrite@resource://devtools/shared/protocol/Response.js:98:22\nwrite@resource://devtools/shared/protocol/Response.js:43:28\nsendReturn@resource://devtools/shared/protocol/Actor.js:164:38\n"
[task 2019-11-07T12:00:03.143Z] 12:00:03 INFO - GECKO(9640) | console.error: "Error writing response to: listWorkers"
[task 2019-11-07T12:00:03.144Z] 12:00:03 INFO - GECKO(9640) | console.error: "Error while calling actor 'contentProcessTarget's method 'listWorkers'" "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIServiceWorkerManager.getRegistrationByPrincipal]"
[task 2019-11-07T12:00:03.144Z] 12:00:03 INFO - GECKO(9640) | console.error: "_getServiceWorkerRegistrationInfo@resource://devtools/server/actors/targets/worker.js:170:16\nform@resource://devtools/server/actors/targets/worker.js:65:35\nwrite@resource://devtools/shared/protocol/types.js:363:32\ntypes.addArrayType/write/<@resource://devtools/shared/protocol/types.js:220:33\nwrite@resource://devtools/shared/protocol/types.js:220:16\nwrite@resource://devtools/shared/protocol/types.js:387:22\nwrite@resource://devtools/shared/protocol/types.js:268:39\nwrite@resource://devtools/shared/protocol/Response.js:98:22\nwrite@resource://devtools/shared/protocol/Response.js:43:28\nsendReturn@resource://devtools/shared/protocol/Actor.js:164:38\n"
[task 2019-11-07T12:00:03.296Z] 12:00:03 INFO - GECKO(9640) | console.error: "Error writing response to: listWorkers"
[task 2019-11-07T12:00:03.296Z] 12:00:03 INFO - GECKO(9640) | console.error: "Error while calling actor 'contentProcessTarget's method 'listWorkers'" "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIServiceWorkerManager.getRegistrationByPrincipal]"
[task 2019-11-07T12:00:03.296Z] 12:00:03 INFO - GECKO(9640) | console.error: "_getServiceWorkerRegistrationInfo@resource://devtools/server/actors/targets/worker.js:170:16\nform@resource://devtools/server/actors/targets/worker.js:65:35\nwrite@resource://devtools/shared/protocol/types.js:363:32\ntypes.addArrayType/write/<@resource://devtools/shared/protocol/types.js:220:33\nwrite@resource://devtools/shared/protocol/types.js:220:16\nwrite@resource://devtools/shared/protocol/types.js:387:22\nwrite@resource://devtools/shared/protocol/types.js:268:39\nwrite@resource://devtools/shared/protocol/Response.js:98:22\nwrite@resource://devtools/shared/protocol/Response.js:43:28\nsendReturn@resource://devtools/shared/protocol/Actor.js:164:38\n"
[task 2019-11-07T12:00:03.296Z] 12:00:03 INFO - GECKO(9640) | console.error: "Error writing response to: listWorkers"
[task 2019-11-07T12:00:03.296Z] 12:00:03 INFO - GECKO(9640) | console.error: "Error while calling actor 'contentProcessTarget's method 'listWorkers'" "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIServiceWorkerManager.getRegistrationByPrincipal]"
[task 2019-11-07T12:00:03.296Z] 12:00:03 INFO - GECKO(9640) | console.error: "_getServiceWorkerRegistrationInfo@resource://devtools/server/actors/targets/worker.js:170:16\nform@resource://devtools/server/actors/targets/worker.js:65:35\nwrite@resource://devtools/shared/protocol/types.js:363:32\ntypes.addArrayType/write/<@resource://devtools/shared/protocol/types.js:220:33\nwrite@resource://devtools/shared/protocol/types.js:220:16\nwrite@resource://devtools/shared/protocol/types.js:387:22\nwrite@resource://devtools/shared/protocol/types.js:268:39\nwrite@resource://devtools/shared/protocol/Response.js:98:22\nwrite@resource://devtools/shared/protocol/Response.js:43:28\nsendReturn@resource://devtools/shared/protocol/Actor.js:164:38\n"
[task 2019-11-07T12:00:03.641Z] 12:00:03 INFO - GECKO(9640) | --DOCSHELL 000001DB5CD5C000 == 7 [pid = 7420] [id = {688dc7ea-5b69-4253-8564-2c9f675e979c}] [url = about:devtools-toolbox]
[task 2019-11-07T12:00:03.908Z] 12:00:03 INFO - GECKO(9640) | --DOMWINDOW == 23 (000001DB6725B400) [pid = 7420] [serial = 739] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:03.908Z] 12:00:03 INFO - GECKO(9640) | --DOMWINDOW == 22 (000001DB6514CC00) [pid = 7420] [serial = 738] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:04.920Z] 12:00:04 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: NS_ENSURE_TRUE(!mHasOrHasHadOwnerWindow || mOwnerWindow) failed: file z:/build/build/src/dom/events/DOMEventTargetHelper.cpp, line 321
[task 2019-11-07T12:00:04.920Z] 12:00:04 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: NS_ENSURE_TRUE(!mHasOrHasHadOwnerWindow || mOwnerWindow) failed: file z:/build/build/src/dom/events/DOMEventTargetHelper.cpp, line 321
[task 2019-11-07T12:00:04.920Z] 12:00:04 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: NS_ENSURE_TRUE(!mHasOrHasHadOwnerWindow || mOwnerWindow) failed: file z:/build/build/src/dom/events/DOMEventTargetHelper.cpp, line 321
[task 2019-11-07T12:00:04.920Z] 12:00:04 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: NS_ENSURE_TRUE(!mHasOrHasHadOwnerWindow || mOwnerWindow) failed: file z:/build/build/src/dom/events/DOMEventTargetHelper.cpp, line 321
[task 2019-11-07T12:00:04.925Z] 12:00:04 INFO - GECKO(9640) | --DOMWINDOW == 21 (000001DB5BBB76A0) [pid = 7420] [serial = 741] [outer = 0000000000000000] [url = chrome://devtools/content/debugger/index.html]
[task 2019-11-07T12:00:04.925Z] 12:00:04 INFO - GECKO(9640) | --DOMWINDOW == 20 (000001DB5BBB74C0) [pid = 7420] [serial = 737] [outer = 0000000000000000] [url = about:devtools-toolbox]
[task 2019-11-07T12:00:07.804Z] 12:00:07 INFO - GECKO(9640) | --DOCSHELL 000001E3E0043800 == 1 [pid = 1856] [id = {0a395e47-8da2-43ad-a29b-930bbaa4c6b1}] [url = about:blank]
[task 2019-11-07T12:00:07.905Z] 12:00:07 INFO - GECKO(9640) | --DOMWINDOW == 4 (000001E3E00AB5C0) [pid = 1856] [serial = 284] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:08.567Z] 12:00:08 INFO - GECKO(9640) | --DOMWINDOW == 19 (000001DB68037C00) [pid = 7420] [serial = 742] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:08.567Z] 12:00:08 INFO - GECKO(9640) | --DOMWINDOW == 18 (000001DB68036000) [pid = 7420] [serial = 740] [outer = 0000000000000000] [url = about:devtools-toolbox]
[task 2019-11-07T12:00:08.567Z] 12:00:08 INFO - GECKO(9640) | --DOMWINDOW == 17 (000001DB5FCAAC00) [pid = 7420] [serial = 745] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:08.567Z] 12:00:08 INFO - GECKO(9640) | --DOMWINDOW == 16 (000001DB5D15C800) [pid = 7420] [serial = 744] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:11.955Z] 12:00:11 INFO - GECKO(9640) | --DOMWINDOW == 3 (000001E3E6065000) [pid = 1856] [serial = 285] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:11.955Z] 12:00:11 INFO - GECKO(9640) | --DOMWINDOW == 2 (000001E3E00D0000) [pid = 1856] [serial = 287] [outer = 0000000000000000] [url = about:blank]
[task 2019-11-07T12:00:16.030Z] 12:00:16 INFO - GECKO(9640) | [Parent 7420, Jump List] WARNING: NS_ENSURE_SUCCESS(rv, rv) failed with result 0x80520012: file z:/build/build/src/widget/windows/WinUtils.cpp, line 1346
[task 2019-11-07T12:00:33.045Z] 12:00:33 INFO - GECKO(9640) | [Parent 7420, Gecko_IOThread] WARNING: pipe error: 109: file z:/build/build/src/ipc/chromium/src/chrome/common/ipc_channel_win.cc, line 341
[task 2019-11-07T12:01:10.450Z] 12:01:10 INFO - JavaScript error: resource://gre/modules/PlacesExpiration.jsm, line 851: TypeError: this._db is undefined
[task 2019-11-07T12:01:29.688Z] 12:01:29 INFO - TEST-INFO | started process screenshot
[task 2019-11-07T12:01:29.767Z] 12:01:29 INFO - TEST-INFO | screenshot: exit 0
[task 2019-11-07T12:01:29.767Z] 12:01:29 INFO - Buffered messages logged at 11:59:59
[task 2019-11-07T12:01:29.767Z] 12:01:29 INFO - Entering test bound
[task 2019-11-07T12:01:29.767Z] 12:01:29 INFO - Adding a new tab with URL: http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html
[task 2019-11-07T12:01:29.767Z] 12:01:29 INFO - Tab added and finished loading
[task 2019-11-07T12:01:29.768Z] 12:01:29 INFO - Opening the toolbox
[task 2019-11-07T12:01:29.768Z] 12:01:29 INFO - Console message: [JavaScript Error: "The character encoding of the HTML document was not declared. The document will render with garbled text in some browser configurations if the document contains characters from outside the US-ASCII range. The character encoding of the page must be declared in the document or in the transfer protocol." {file: "http://example.com/browser/devtools/client/debugger/test/mochitest/examples/doc-service-workers.html" line: 0}]
[task 2019-11-07T12:01:29.768Z] 12:01:29 INFO - Buffered messages logged at 12:00:00
[task 2019-11-07T12:01:29.768Z] 12:01:29 INFO - Console message: [JavaScript Error: "Content Security Policy: The page’s settings blocked the loading of a resource at inline (“default-src”)." {file: "chrome://global/content/elements/panel.js" line: 62}]
[task 2019-11-07T12:01:29.768Z] 12:01:29 INFO - Buffered messages logged at 12:00:02
[task 2019-11-07T12:01:29.769Z] 12:01:29 INFO - Toolbox opened and focused
[task 2019-11-07T12:01:29.769Z] 12:01:29 INFO - Invoking in tab: registerWorker()
[task 2019-11-07T12:01:29.769Z] 12:01:29 INFO - Waiting for state change: source exists
[task 2019-11-07T12:01:29.769Z] 12:01:29 INFO - Buffered messages finished
[task 2019-11-07T12:01:29.769Z] 12:01:29 INFO - TEST-UNEXPECTED-FAIL | devtools/client/debugger/test/mochitest/browser_dbg-windowless-service-workers.js | Test timed out -
[task 2019-11-07T12:01:30.841Z] 12:01:30 INFO - Removing tab.
[task 2019-11-07T12:01:30.841Z] 12:01:30 INFO - Waiting for event: 'TabClose' on [object XULElement].
[task 2019-11-07T12:01:30.860Z] 12:01:30 INFO - Got event: 'TabClose' on [object XULElement].
[task 2019-11-07T12:01:30.878Z] 12:01:30 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: '!inner', file z:/build/build/src/dom/ipc/JSWindowActorService.cpp, line 172
[task 2019-11-07T12:01:30.878Z] 12:01:30 INFO - GECKO(9640) | [Parent 7420, Main Thread] WARNING: '!contentChild', file z:/build/build/src/dom/base/ContentBlockingLog.cpp, line 133
[task 2019-11-07T12:01:30.878Z] 12:01:30 INFO - Tab removed and finished closing
[task 2019-11-07T12:01:30.900Z] 12:01:30 INFO - GECKO(9640) | --DOCSHELL 000001DB5BBE3000 == 6 [pid = 7420] [id = {c32f6b9a-61a5-4834-86f6-54734860839e}] [url = chrome://devtools/content/debugger/index.html]
[task 2019-11-07T12:01:30.921Z] 12:01:30 INFO - TEST-PASS | devtools/client/debugger/test/mochitest/browser_dbg-windowless-service-workers.js | The main process DebuggerServer has no pending connection when the test ends -
[task 2019-11-07T12:01:30.966Z] 12:01:30 INFO - GECKO(9640) | MEMORY STAT | vsize 2104668MB | vsizeMaxContiguous 68249657MB | residentFast 505MB | heapAllocated 149MB
[task 2019-11-07T12:01:30.966Z] 12:01:30 INFO - TEST-OK | devtools/client/debugger/test/mochitest/browser_dbg-windowless-service-workers.js | took 91317ms

Brian, can you take a look at this?

Hmm, I'm having trouble reproducing this locally. I'm following the directions at https://wiki.mozilla.org/Sheriffing/How_To/Beta_simulations#TRUNK_AS_EARLY_BETA and doing a clean build, but afterwards if I try to run a mochitest it fails --- a window appears and then disappears and no tests run, and I get the output below. Is this a known problem?

Brians-MacBook-Pro-2:mozilla-inbound7 bhackett$ ./mach mochitest devtools/client/debugger/
 0:00.20 INFO Checking for ssltunnel processes...
 0:00.21 INFO Checking for xpcshell processes...
 0:00.23 SUITE_START: mochitest-browser - running 132 tests
 0:00.23 TEST_START: devtools/client/debugger/test/mochitest/browser_dbg-reloading.js
 0:00.23 TEST_END: SKIP
 0:00.23 TEST_START: devtools/client/debugger/test/mochitest/browser_dbg-sourcemapped-stepping.js
 0:00.23 TEST_END: SKIP
 0:00.23 TEST_START: devtools/client/debugger/test/mochitest/browser_dbg-sources-querystring.js
 0:00.23 TEST_END: SKIP
 0:00.23 INFO Running manifest: devtools/client/debugger/test/mochitest/browser.ini
pk12util: PKCS12 IMPORT SUCCESSFUL
 0:00.65 INFO MochitestServer : launching [u'/Users/bhackett/mozilla-inbound7/ff-opt/dist/bin/xpcshell', '-g', u'/Users/bhackett/mozilla-inbound7/ff-opt/dist/Nightly.app/Contents/Resources', '-f', u'/Users/bhackett/mozilla-inbound7/ff-opt/dist/bin/components/httpd.js', '-e', "const _PROFILE_PATH = '/var/folders/qb/hkxh7qyj3zq4h91y4s7_slyw0000gn/T/tmpfyzZjS.mozrunner'; const _SERVER_PORT = '8888'; const _SERVER_ADDR = '127.0.0.1'; const _TEST_PREFIX = undefined; const _DISPLAY_RESULTS = false;", '-f', '/Users/bhackett/mozilla-inbound7/ff-opt/_tests/testing/mochitest/server.js']
 0:00.65 INFO runtests.py | Server pid: 96932
 0:00.65 INFO runtests.py | Websocket server pid: 96933
 0:00.66 INFO runtests.py | SSL tunnel pid: 96934
 0:00.77 INFO runtests.py | Running with scheme: http
 0:00.77 INFO runtests.py | Running with e10s: True
 0:00.77 INFO runtests.py | Running with fission: False
 0:00.77 INFO runtests.py | Running with serviceworker_e10s: False
 0:00.77 INFO runtests.py | Running with socketprocess_e10s: False
 0:00.77 INFO runtests.py | Running tests: start.

 0:00.78 WARNING Found 'firefox' running before starting test browser!
 0:00.78 WARNING {'username': 'bhackett', 'cmdline': ['/Applications/Firefox Nightly.app/Contents/MacOS/firefox'], 'ppid': 1, 'pid': 66536, 'name': 'firefox'}

 0:00.78 INFO Application command: /Users/bhackett/mozilla-inbound7/ff-opt/dist/Nightly.app/Contents/MacOS/firefox -marionette -foreground -profile /var/folders/qb/hkxh7qyj3zq4h91y4s7_slyw0000gn/T/tmpfyzZjS.mozrunner
 0:00.79 INFO runtests.py | Application pid: 96935
 0:00.79 Started process `GECKO(96935)`
 0:01.25 GECKO(96935) 1573229132431	addons.webextension.screenshots@mozilla.org	WARN	Loading extension 'screenshots@mozilla.org': Reading manifest: Invalid extension permission: mozillaAddons
 0:01.25 GECKO(96935) 1573229132433	addons.webextension.screenshots@mozilla.org	WARN	Loading extension 'screenshots@mozilla.org': Reading manifest: Invalid extension permission: telemetry
 0:01.25 GECKO(96935) 1573229132433	addons.webextension.screenshots@mozilla.org	WARN	Loading extension 'screenshots@mozilla.org': Reading manifest: Invalid extension permission: resource://pdf.js/
 0:01.25 GECKO(96935) 1573229132433	addons.webextension.screenshots@mozilla.org	WARN	Loading extension 'screenshots@mozilla.org': Reading manifest: Invalid extension permission: about:reader*
 0:01.33 GECKO(96935) 1573229132518	Marionette	TRACE	Received observer notification profile-after-change
 0:01.41 GECKO(96935) 1573229132599	Marionette	TRACE	Received observer notification command-line-startup
 0:01.41 GECKO(96935) 1573229132600	Marionette	DEBUG	Init aborted (running=false, enabled=true, finalUIStartup=false)
 0:01.54 GECKO(96935) 1573229132729	Marionette	TRACE	Received observer notification toplevel-window-ready
 0:02.29 GECKO(96935) [GFX1-]: Receive IPC close with reason=AbnormalShutdown
 0:02.30 GECKO(96935) Exiting due to channel error.

This sounds like it complains about a different Firefox browser running? Does it work if you close your main browser? Can you pass --no-remote?

Brian, did you make any progress here?

Sorry for the delay, I'll look into this again today.

Attaching to service workers in this test is failing if parent intercept mode is not enabled, which is the case in non-nightly builds.

https://hg.mozilla.org/mozilla-central/rev/642d11091f62

Verified fixed in today's central as beta simulation: https://treeherder.mozilla.org/#/jobs?repo=try&selectedJob=277628704&resultStatus=success%2Ctestfailed%2Cbusted%2Cexception%2Crunnable&revision=f1c365e9bf21220130335842a7008f057a3eafb0&searchStr=(bc&group_state=expanded