Use flutter repo for engine golds instead of flutter-engine.

[matanlurey]

Closes #157206.

I also added a prefix that will default to engine. to avoid accidentally stomping on golden names across repos.

/cc @gaaclarke for visibility, @Piinks for visibility.

(I would love to get rid of this "engine copy" of the client as part of longer-term mono repo deduplication).

[gaaclarke]

Why do we have to make this change? Isn't this going to invalidate all of our history? I don't know if there is any benefit of starting to upload our goldens to the flutter golden endpoint.

[Piinks]

Why do we have to make this change? Isn't this going to invalidate all of our history? I don't know if there is any benefit of starting to upload our goldens to the flutter golden endpoint.

Engine golden files in flutter/flutter monorepo land will not be able to use the engine instance of Gold. Gold instances are correlated with a repo and track commits only from that repo.

[flutter-dashboard]

Golden file changes have been found for this pull request. Click here to view and triage (e.g. because this is an intentional change).

If you are still iterating on this change and are not ready to resolve the images on the Flutter Gold dashboard, consider marking this PR as a draft pull request above. You will still be able to view image results on the dashboard, commenting will be silenced, and the check will not try to resolve itself until marked ready for review.

For more guidance, visit Writing a golden file test for package:flutter.

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

Changes reported for pull request #160556 at sha 2564473

[jonahwilliams]

LGTM

[jtmcdole]

[matanlurey]

This PR keeps failing in merge queue despite passing in presubmit.

Example failure, 1 of ~200:

stdout: Given image with hash 3f5895ca785071873070f39b6ee018d2 for test engine.canvas_test_toImage
Fetching most recent positive digest for trace with ID "d378d6587de23311f96d6cbdf6daa26f".
No recent positive digests for trace with ID "d378d6587de23311f96d6cbdf6daa26f". This probably means that the test was newly added.
Non-exact image comparison using algorithm "fuzzy" against most recent positive digest "".
Untriaged or negative image

The same test in the presubmit reports the same failure:

NOTE: Untriaged image detected in tryjob.
Triage should be required by the "Flutter Gold" check
stdout:
Given image with hash 43af40a9baa67b933cde8f2dac7f28ac for test engine.canvas_test_toImage
Expectation for test: 3f5895ca785071873070f39b6ee018d2 (positive)
Fetching most recent positive digest for trace with ID "3c059772c4ee1ae45c84a335b2849854".
No recent positive digests for trace with ID "3c059772c4ee1ae45c84a335b2849854". This probably means that the test was newly added.
Non-exact image comparison using algorithm "fuzzy" against most recent positive digest "".
Untriaged or negative image

... but the flutter-gold check is not reporting anything.

It's worth noting I see the "double patchset" which in the past has meant bad state has occurred somehow: