Bug 1965821 [wpt PR 52475] - Use external length resolver to resolve UnresolvedRelativeColor,

Automatic update from web-platform-tests
Use external length resolver to resolve UnresolvedRelativeColor

For now, the constructor is creating default conversion data with
a nullptr element.

No behavior changes expected, as it will be resolved later instead
of at parse time.

Also, don't try to resolve at parse time.

Bug: 416454066
Change-Id: Iabebb4862548072f805f52f16016ecc2f5d05b7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6530103
Commit-Queue: Daniil Sakhapov <sakhapovchromium.org>
Reviewed-by: Rune Lillesveen <futharkchromium.org>
Cr-Commit-Position: refs/heads/main{#1458755}

--

wpt-commits: 8d88b6f85af9defdd5dc08ad34fab28f6ea23b09
wpt-pr: 52475

Differential Revision: https://phabricator.services.mozilla.com/D249366

UltraBlame original commit: 8406ba10a754f3822a8d9bd9aa02390dd1a070b4

Author: marco-c

testing/web-platform/tests/css/css-color/parsing/color-computed-relative-color.html

@@ -871,6 +871,7 @@
   fuzzy_test_computed_color(`lch(from var(--mycolor) l 0 h)`, `lch(62.75 0 326.96)`, 0.02);
   fuzzy_test_computed_color(`var(--mygray)`, `lch(62.75 0 326.96)`, 0.02);
   fuzzy_test_computed_color(`lch(from var(--mygray) l 30 h)`, `lch(62.75 30 326.96)`, 0.02);
+  fuzzy_test_computed_color(`LCH(from var(--accent) l c calc(h + 180 * sibling-index()))`, `lch(65.49 39.45 10.11)`, 0.02);
 </script>
 </body>
 </html>