1820661 - Update image-set to draw nothing when all provided images use an unsupported "type" param

Status: RESOLVED FIXED

(Core :: Layout: Images, Video, and HTML Frames, defect)

Description

[Daniel Holbert [:dholbert]]

Following up on bug 1806025... It seems the spec has been updated (in https://github.com/w3c/csswg-drafts/issues/8266 ) to require something other than what we implement, and the new spec language probably makes sense, so we should update our implementation to align to it.

(Right now, when none of the images have a valid "type" parameter, our impl uses the first one, as noted in the extended commit message of https://hg.mozilla.org/mozilla-central/rev/6cc8cc1231f4 . But the spec now requires that we treat the whole thing as transparent-black, essentially as if there were no image.)

With this change, we'll start passing these two tests again:
https://wpt.fyi/results/css/css-images/image-set/image-set-type-unsupported-rendering.html
https://wpt.fyi/results/css/css-images/image-set/image-set-type-unsupported-rendering-2.html

(We passed them previously, with emilio's test-edit in bug 1806025, but we stopped passing them when their reference-case-expectation was updated in response to the above github spec-issue, here:
https://github.com/web-platform-tests/wpt/commit/1ba5cfed0836d1f7ea78b115ef6d9c7ed767b8b9
)

Comment 1

[Daniel Holbert [:dholbert]]

(toggling needinfo to be sure this on emilio's radar to fix or mentor, since I think he's closest to this code.)

Comment 2

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 1820661 - Make image-set without valid images render nothing. r=#layout,#style

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ec3e1815f56b
Make image-set without valid images render nothing. r=dholbert

Comment 4

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/ec3e1815f56b