Filed by: nerli [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=290968779&repo=autoland
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/BwBWkrNuSTCt3A4fLx7Sbw/runs/0/artifacts/public/logs/live_backing.log
Reftest URL: https://hg.mozilla.org/mozilla-central/raw-file/tip/layout/tools/reftest/reftest-analyzer.xhtml#logurl=https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/BwBWkrNuSTCt3A4fLx7Sbw/runs/0/artifacts/public/logs/live_backing.log&only_show_unexpected=1

[task 2020-02-28T12:55:55.644Z] 12:55:55 INFO - TEST-INFO | Main app process: exit 0
[task 2020-02-28T12:55:55.644Z] 12:55:55 INFO - TEST-INFO | Confirming we saw 103 DOCSHELL created and 103 destroyed log strings.
[task 2020-02-28T12:55:55.645Z] 12:55:55 INFO - TEST-INFO | Confirming we saw 272 DOMWINDOW created and 272 destroyed log strings.
[task 2020-02-28T12:55:55.645Z] 12:55:55 ERROR - TEST-UNEXPECTED-FAIL | devtools/client/aboutdebugging/test/browser/browser_aboutdebugging_devtoolstoolbox_focus.js | leaked 2 window(s) until shutdown [url = about:devtools-toolbox?type=tab&id=49]
[task 2020-02-28T12:55:55.645Z] 12:55:55 ERROR - TEST-UNEXPECTED-FAIL | devtools/client/aboutdebugging/test/browser/browser_aboutdebugging_devtoolstoolbox_focus.js | leaked 2 window(s) until shutdown [url = about:debugging]
[task 2020-02-28T12:55:55.645Z] 12:55:55 ERROR - TEST-UNEXPECTED-FAIL | devtools/client/aboutdebugging/test/browser/browser_aboutdebugging_devtoolstoolbox_focus.js | leaked 1 window(s) until shutdown [url = chrome://devtools/content/performance/index.xhtml]
[task 2020-02-28T12:55:55.645Z] 12:55:55 ERROR - TEST-UNEXPECTED-FAIL | devtools/client/aboutdebugging/test/browser/browser_aboutdebugging_devtoolstoolbox_focus.js | leaked 1 window(s) until shutdown [url = about:blank]
[task 2020-02-28T12:55:55.646Z] 12:55:55 INFO - TEST-INFO | devtools/client/aboutdebugging/test/browser/browser_aboutdebugging_devtoolstoolbox_focus.js | windows(s) leaked: [pid = 9552] [serial = 33], [pid = 9552] [serial = 34], [pid = 9552] [serial = 29], [pid = 9552] [serial = 30], [pid = 9552] [serial = 35], [pid = 9552] [serial = 27]
[task 2020-02-28T12:55:55.646Z] 12:55:55 INFO - TEST-INFO | devtools/client/aboutdebugging/test/browser/browser_aboutdebugging_devtoolstoolbox_focus.js | This test created 1 hidden window(s)
[task 2020-02-28T12:55:55.649Z] 12:55:55 INFO - TEST-INFO | devtools/client/aboutdebugging/test/browser/browser_aboutdebugging_devtoolstoolbox_focus.js | This test created 1 hidden docshell(s)

https://wiki.mozilla.org/Bug_Triage#Intermittent_Test_Failure_Cleanup
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