Filed by: rmaries [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=308560462&repo=autoland
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/WgjuUySlRSGGt9a4Lmjs7g/runs/0/artifacts/public/logs/live_backing.log

[task 2020-07-04T10:32:51.383Z] 10:32:51 INFO - TEST-START | browser/components/sessionstore/test/browser_restore_redirect.js
[task 2020-07-04T10:34:21.871Z] 10:34:21 INFO - Buffered messages finished
[task 2020-07-04T10:34:21.872Z] 10:34:21 INFO - TEST-UNEXPECTED-FAIL | browser/components/sessionstore/test/browser_restore_redirect.js | Test timed out -
[task 2020-07-04T10:34:21.872Z] 10:34:21 INFO - GECKO(2680) | MEMORY STAT | vsize 3508MB | residentFast 421MB | heapAllocated 113MB
[task 2020-07-04T10:34:21.874Z] 10:34:21 INFO - TEST-OK | browser/components/sessionstore/test/browser_restore_redirect.js | took 90229ms
[task 2020-07-04T10:34:21.874Z] 10:34:21 INFO - Not taking screenshot here: see the one that was previously logged
[task 2020-07-04T10:34:21.874Z] 10:34:21 INFO - TEST-UNEXPECTED-FAIL | browser/components/sessionstore/test/browser_restore_redirect.js | Found a tab after previous test timed out: http://example.com/browser/browser/components/sessionstore/test/restore_redirect_js.html -
[task 2020-07-04T10:34:21.875Z] 10:34:21 INFO - GECKO(2680) | JavaScript error: resource://gre/modules/sessionstore/SessionHistory.jsm, line 109: TypeError: can't access property "legacySHistory", history is null
[task 2020-07-04T10:34:21.878Z] 10:34:21 INFO - GECKO(2680) | [Child 2809: Main Thread]: I/DocShellAndDOMWindowLeak ++DOCSHELL 0x7f8818dab000 == 1 [pid = 2809] [id = {5d30d0bd-1c18-47f8-a765-80ed98a80b00}]
[task 2020-07-04T10:34:21.878Z] 10:34:21 INFO - GECKO(2680) | [Child 2809: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 1 (0x7f8835f93350) [pid = 2809] [serial = 447] [outer = (nil)]
[task 2020-07-04T10:34:21.879Z] 10:34:21 INFO - GECKO(2680) | [Child 2809: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 2 (0x7f8818dac400) [pid = 2809] [serial = 448] [outer = 0x7f8835f93350]
[task 2020-07-04T10:34:21.881Z] 10:34:21 INFO - GECKO(2680) | [Child 2809: Main Thread]: I/DocShellAndDOMWindowLeak ++DOMWINDOW == 3 (0x7f8818db1800) [pid = 2809] [serial = 449] [outer = 0x7f8835f93350]
[task 2020-07-04T10:34:21.881Z] 10:34:21 INFO - checking window state

It is the same as bug 1647109.

https://wiki.mozilla.org/Bug_Triage#Intermittent_Test_Failure_Cleanup
For more information, please visit auto_nag documentation.