Bug 1998544 [wpt PR 55877] - Allow <string> in the animation-name CSS property, a=testonly

Automatic update from web-platform-tests
Allow <string> in the animation-name CSS property

The animation-name property syntax allows both <custom-ident> and
<string> values. There were some doubts [1] about the serialization of
this property due to potential conflicts between the <string> values and
some identifies in the css-wide group.

The CSSWG resolution was to serialize this property as custom-ident when
possible, and as strings otherwise.

This CL aligns Chrome with Firefox and Safari as well as other minor
engines like Servo and Ladybird.

[1] w3c/csswg-drafts#2435

Bug: 40592875
Change-Id: I4851c8605a514dbe1d47d8898ae7925378bbdb08
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7067893
Reviewed-by: Anders Hartvoll Ruud <andruudchromium.org>
Commit-Queue: Javier Fernandez <jfernandezigalia.com>
Cr-Commit-Position: refs/heads/main{#1541685}

--

wpt-commits: 5ded9c243a8273f95a8aacd07b115f952516cbbf
wpt-pr: 55877

UltraBlame original commit: d14cbfc0bff9ae453ba74456c6bd1e6de195ed32

Author: marco-c

testing/web-platform/tests/css/css-animations/parsing/animation-name-invalid.html

@@ -20,6 +20,8 @@
 test_invalid_value("animation-name", 'default, two');
 test_invalid_value("animation-name", 'revert, three');
 test_invalid_value("animation-name", 'revert-layer, four');
+
+test_invalid_value("animation-name", '""');
 </script>
 </body>
 </html>