1544121 - size containment should make replaced elements behave as if they were 0x0

Status: RESOLVED FIXED

(Core :: Layout, defect, P3)

Description

[Daniel Holbert [:dholbert]]

Attachment: testcase 1

I just noticed this in the size containment spec text:

Replaced elements must be treated as having an intrinsic width and height of 0.

https://drafts.csswg.org/css-contain/#containment-size

We need to implement this part.

Testcase attached, with some replaced elements all of which have contain:size and should be rendered with a content-box size of 0x0.

Comment 1

[Daniel Holbert [:dholbert]]

For comparison, Chrome renders nearly every element in the testcase with a 0x0 content-box, with one exception: they render <audio controls> as a full-size audio widget -- this is a Chrome bug, because this element is definitely expected to be treated as a replaced element per https://html.spec.whatwg.org/multipage/rendering.html#embedded-content-rendering-rules :

The audio element, when it is exposing a user interface, is expected to be treated as a replaced element

(where I believe "exposing a user interface" means "has the controls attribute", basically)

I filed https://bugs.chromium.org/p/chromium/issues/detail?id=952414 on this Chrome bug.

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: Bug 1544121: Make size-contained replaced elements behave as if they had 0x0 intrinsic size and ratio. r?TYLin

Comment 3

[Daniel Holbert [:dholbert]]

Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=e726dfbfb5ef9acb75c5bcecc6cd855ef6db7808

Comment 4

[Daniel Holbert [:dholbert]]

Note that Chrome doesn't quite pass the new WPT tests -- the first one (contain-size-replaced-003a.html ) fails due to the Chrome bug that I linked above:
https://bugs.chromium.org/p/chromium/issues/detail?id=952414
and the other two (003b.html and 003c.html) fail due to:
https://bugs.chromium.org/p/chromium/issues/detail?id=955163

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/792aae9f893a
Make size-contained replaced elements behave as if they had 0x0 intrinsic size and ratio. r=TYLin

Comment 6

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/792aae9f893a

Comment 7

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/16699 for changes under testing/web-platform/tests