[webkit-changes] [WebKit/WebKit] 4b4a31: Fix CSS.supports behaviour with regards to !import...

[Ahmad Saleem]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 4b4a31ba711780267092644970214807bc0cfbac
      https://github.com/WebKit/WebKit/commit/4b4a31ba711780267092644970214807bc0cfbac
  Author: Ahmad Saleem <ahmad.saleem792+github at gmail.com>
  Date:   2022-11-30 (Wed, 30 Nov 2022)

  Changed paths:
    M LayoutTests/css3/supports-dom-api-expected.txt
    M LayoutTests/css3/supports-dom-api.html
    M Source/WebCore/css/DOMCSSNamespace.cpp

  Log Message:
  -----------
  Fix CSS.supports behaviour with regards to !important and whitespace

Fix CSS.supports behaviour with regards to !important and whitespace
https://bugs.webkit.org/show_bug.cgi?id=248450

Reviewed by Antti Koivisto.

This patch is to align Webkit with Blink / Chromium, Gecko / Firefox and Web-Specification.

Web-Spec:

[1] https://drafts.csswg.org/css-conditional-3/#the-csssupportsrule-interface
[2] https://drafts.csswg.org/cssom-1/#dom-cssstyledeclaration-setpropertyvalue

Merge - https://chromium.googlesource.com/chromium/blink/+/36890765b05b48d8065737682b4e878645b601b2

This patch changes some small issues in CSS.supports:

1) Whitespace in CSS properties are not allowed. This aligns with FF and
the spec.
2) !important in a value is not removed. The !important flag is not part
of a CSS value, so something like CSS.supports("left","10px !important")
should return false. This is not completely clear in the spec but likely
the intended behaviour and similar to CSSStyleDeclaration from the CSSOM
(which says 'value can not include "!important"' for setProperty).
3) Newlines are not turned into spaces. These are not equivalent in CSS,
as newlines will cause strings to become bad string tokens.

* Source/WebCore/css/DOMCSSNamespace.cpp:
(valeWithoutImportant): Removed
(DOMCSSNamespace::supports): Update to remove "whitespace" and return 'value' rather than 'normalizedValue'
* LayoutTests/css3/supports-dom-api.html: Rebaselined
* LayoutTests/css3/supports-dom-api-expected.txt: Rebaselined

Canonical link: https://commits.webkit.org/257196@main