Filed by: apavel [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=267180361&repo=autoland
Full log: https://queue.taskcluster.net/v1/task/JpOJ3GmDR4qzYUMX7c-zKw/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://queue.taskcluster.net/v1/task/JpOJ3GmDR4qzYUMX7c-zKw/runs/0/artifacts/public/logs/live_backing.log&only_show_unexpected=1

[task 2019-09-18T05:04:34.349Z] 05:04:34 INFO - REFTEST TEST-START | http://10.7.205.213:8854/tests/layout/reftests/text-stroke/webkit-text-stroke-property-002.html == http://10.7.205.213:8854/tests/layout/reftests/text-stroke/webkit-text-stroke-property-002-ref.html
[task 2019-09-18T05:04:34.349Z] 05:04:34 INFO - REFTEST TEST-LOAD | http://10.7.205.213:8854/tests/layout/reftests/text-stroke/webkit-text-stroke-property-002.html | 654 / 1931 (33%)
[task 2019-09-18T05:04:34.349Z] 05:04:34 INFO - REFTEST TEST-LOAD | http://10.7.205.213:8854/tests/layout/reftests/text-stroke/webkit-text-stroke-property-002-ref.html | 654 / 1931 (33%)
[task 2019-09-18T05:04:34.349Z] 05:04:34 INFO - REFTEST INFO | REFTEST fuzzy test (0, 0) <= (4, 299) <= (3, 1476)
[task 2019-09-18T05:04:34.349Z] 05:04:34 INFO - REFTEST TEST-UNEXPECTED-FAIL | http://10.7.205.213:8854/tests/layout/reftests/text-stroke/webkit-text-stroke-property-002.html == http://10.7.205.213:8854/tests/layout/reftests/text-stroke/webkit-text-stroke-property-002-ref.html | image comparison, max difference: 4, number of differing pixels: 299

Hi Emilio, this showed up when bug 1578661 landed, can it be from there?

No. This is WebRender only, it's way more likely from being from the recent blob changes Nical and Jeff have been doing.