Dup of bug 1422437 ?

No, mozscreenshots (browser/tools/mozscreenshots) is used in automation, it is different from the user-facing "Firefox Screenshots" which is tracked in the bug you referenced.

Some notes on the attached patch: Try run (linux only): https://treeherder.mozilla.org/#/jobs?repo=try&revision=6074032793d08954ad15b888fbcced4ca7767c43 Screenshots comparison page from try run: https://screenshots.mattn.ca/compare/?oldProject=mozilla-central&oldRev=0d4e73bc2cd705d7a021c75a0e8aeb174ab4db59&newProject=try&newRev=951897fd2313dc374b606564cb65b28391338c98 One quirk with the port is that I converted all the extension urls from chrome: to resource: This was mostly fine except for the devtools tests which apparently relied on this code: https://searchfox.org/mozilla-central/rev/a11c128b90ea85d7bb68f00c5de52c0794e0b215/browser/tools/mozscreenshots/mozscreenshots/extension/TestRunner.jsm#211 When navigating from a chrome: url to a data: url, this was a remoteness change which tore down the old browser and closed devtools gracefully. When the page being tested switched to resource:, that navigation just became a regular navigation that left devtools open. This led to a race during shutdown that caused test hangs. I addressed this by having browser_devtools.js explicitly clean up which isn't the tidiest solution but it was expedient...

Updated comparison between a try push based on m-c and a try push with the patches applied: https://screenshots.mattn.ca/compare/?oldProject=try&oldRev=a0aa8da7e8554476a3c14f53fc0a39664abc2ebc&newProject=try&newRev=36a34fe0930ac79b3d9f5d48ac626caad20d7a94

Even new comparison: https://screenshots.mattn.ca/compare/?oldProject=try&oldRev=a0aa8da7e8554476a3c14f53fc0a39664abc2ebc&newProject=try&newRev=a2ab8658c809173960961d1ba3d897abcebbb456 There are a bunch of differences, many of them one-time changes related to pages used in the tests changing urls (from chrome: to resource:). The rest appear to be inconsistencies that are not currently flagged as such in the comparison backend.

Pushed by aswan@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/e8f0ddeec2f1 Convert mozscreenshots to a webextension r=MattN