Bug 1623347 [wpt PR 22318] - [css-variables] Custom props with invali…

…d var() should behave as 'unset', a=testonly

Automatic update from web-platform-tests
[css-variables] Custom props with invalid var() should behave as 'unset'

We currently have a (WPT-enforced) bug where custom properties that
reference guaranteed-invalid values [1] behave themselves as guaranteed-
invalid. This is not correct per spec, which requires the custom
property to behave as 'unset' in this case. This was clarified in [2],
although the spec has described this behavior long before that.

Unfortunately Firefox has the same issue. Safari on the other hand, does
implement it correctly.

[1] https://drafts.csswg.org/css-variables/#guaranteed-invalid
[2] w3c/csswg-drafts#4075

Bug: 980930
Change-Id: I84a0da3aad6b72b574009d560eb868632769098a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2108026
Commit-Queue: Anders Hartvoll Ruud <andruudchromium.org>
Reviewed-by: Xiaocheng Hu <xiaochenghchromium.org>
Cr-Commit-Position: refs/heads/master{#751636}

--

wpt-commits: fc793094912b67b45a94d101819bffb9b9307710
wpt-pr: 22318

UltraBlame original commit: aaae9e1c209687addde4400f03ab390667307b15

testing/web-platform/tests/css/css-env/env-in-custom-properties.tentative.html

@@ -90,7 +90,18 @@
 <
 style
 >
-body
+#
+parent
+{
+-
+-
+var1
+:
+inherited
+;
+}
+#
+child
 {
 -
 -
@@ -115,6 +126,15 @@
 width
 )
 ;
+-
+-
+var1
+:
+env
+(
+nonexistent
+)
+;
 }
 <
 /
@@ -128,6 +148,30 @@
 body
 >
 <
+div
+id
+=
+"
+parent
+"
+>
+<
+div
+id
+=
+"
+child
+"
+>
+<
+/
+div
+>
+<
+/
+div
+>
+<
 script
 >
 test
@@ -144,9 +188,7 @@
 .
 getComputedStyle
 (
-document
-.
-body
+child
 )
 ;
 assert_equals
@@ -165,6 +207,64 @@
 )
 ;
 }
+'
+env
+(
+)
+is
+substituted
+into
+a
+custom
+property
+'
+)
+;
+test
+(
+(
+)
+=
+>
+{
+const
+style
+=
+window
+.
+getComputedStyle
+(
+child
+)
+;
+assert_equals
+(
+style
+.
+getPropertyValue
+(
+"
+-
+-
+var1
+"
+)
+"
+inherited
+"
+)
+;
+}
+'
+Substitution
+of
+unrecognized
+env
+(
+)
+causes
+unset
+'
 )
 ;
 <