Recent failure https://treeherder.mozilla.org/#/jobs?repo=mozilla-central&revision=a73077366144b9699555a1c6f96507d3f353be9b&searchStr=android%2C7.0%2Cx86-64%2Copt%2Cweb%2Cplatform%2Ctests%2Ctest-android-em-7.0-x86_64%2Fopt-web-platform-tests-e10s-7%2Cw%28wpt7%29

Failure log https://treeherder.mozilla.org/logviewer.html#?job_id=249492339&repo=mozilla-central

Part of that log [task 2019-05-31T23:03:57.400Z] 23:03:57 INFO - TEST-START | /html/browsers/the-window-object/garbage-collection-and-browsing-contexts/discard_iframe_history_4.html
[task 2019-05-31T23:03:57.403Z] 23:03:57 INFO - Closing window 2147483671
[task 2019-05-31T23:03:57.411Z] 23:03:57 INFO - Closing window 2147483674
[task 2019-05-31T23:09:57.513Z] 23:09:57 INFO - IOError on command, setting status to CRASH
[task 2019-05-31T23:09:57.734Z] 23:09:57 INFO - TEST-UNEXPECTED-CRASH | /html/browsers/the-window-object/garbage-collection-and-browsing-contexts/discard_iframe_history_4.html | expected OK
[task 2019-05-31T23:09:57.734Z] 23:09:57 INFO - TEST-INFO took 360336ms
[task 2019-05-31T23:09:58.735Z] 23:09:58 INFO - Closing logging queue
[task 2019-05-31T23:09:58.735Z] 23:09:58 INFO - queue closed
[task 2019-05-31T23:09:58.751Z] 23:09:58 INFO - Setting up ssl
[task 2019-05-31T23:09:58.792Z] 23:09:58 INFO - certutil |
[task 2019-05-31T23:09:58.836Z] 23:09:58 INFO - certutil |
[task 2019-05-31T23:09:58.859Z] 23:09:58 INFO - certutil |
[task 2019-05-31T23:09:58.860Z] 23:09:58 INFO - Certificate Nickname Trust Attributes
[task 2019-05-31T23:09:58.860Z] 23:09:58 INFO - SSL,S/MIME,JAR/XPI
[task 2019-05-31T23:09:58.860Z] 23:09:58 INFO -
[task 2019-05-31T23:09:58.860Z] 23:09:58 INFO - web-platform-tests CT,,
[task 2019-05-31T23:09:58.860Z] 23:09:58 INFO -
[task 2019-05-31T23:10:00.728Z] 23:10:00 INFO - adb Granting important runtime permissions to org.mozilla.geckoview.test
[task 2019-05-31T23:10:02.002Z] 23:10:02 INFO - adb launch_application: am start -W -n org.mozilla.geckoview.test/org.mozilla.geckoview.test.TestRunnerActivity -a android.intent.action.MAIN --es env9 MOZ_PROCESS_LOG=/tmp/tmpMk8n0Zpidlog --es env8 MOZ_CRASHREPORTER_NO_REPORT=1 --es args "-no-remote -profile /sdcard/tests/profile --marionette about:blank" --es env3 STYLO_THREADS=4 --es env2 MOZ_HIDE_RESULTS_TABLE=1 --es env1 R_LOG_VERBOSE=1 --es env0 MOZ_CRASHREPORTER=1 --es env7 MOZ_DISABLE_NONLOCAL_CONNECTIONS=1 --es env6 R_LOG_DESTINATION=stderr --es env5 MOZ_CRASHREPORTER_SHUTDOWN=1 --es env4 MOZ_LOG=signaling:3,mtransport:4,DataChannel:4,jsep:4 --ez use_multiprocess True --es env10 R_LOG_LEVEL=6
[task 2019-05-31T23:10:03.889Z] 23:10:03 INFO - Starting runner
[task 2019-05-31T23:10:04.388Z] 23:10:04 INFO - TEST-START | /html/dom/historical.html

No recorded failures after August. Marking WFM.