Bug 1567821 [wpt PR 17967] - [css-properties-values-api] Fix handling of 'em' unit cycles., a=testonly

Automatic update from web-platform-tests
[css-properties-values-api] Fix handling of 'em' unit cycles.

We would incorrectly trigger fallback behavior inside the cycle, which
is not correct. Additionally, the custom property responsible for the
cycle would get 'unset' behavior, which is not correct for custom
properties in a cycle. They should become "invalid at computed-value
time", not unset.

Change-Id: I3865e1c17da06fe7688d2760bde120abff990d85
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1708073
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Anders Hartvoll Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/master@{#679505}

--

wpt-commits: dfac707fc3589d1ef088620111d3ea065f47e472
wpt-pr: 17967

testing/web-platform/tests/css/css-properties-values-api/unit-cycles.html

@@ -96,19 +96,19 @@
     test(function() {
         target.style = 'font-size: var(--font-size-em);';
         assert_property_equals('font-size', unsetFontSize);
-        assert_property_equals('--font-size-em', compute_dimension('2em', 'unset'));
+        assert_property_equals('--font-size-em', '');
     }, 'Lengths with em units may not be referenced from font-size');
 
     test(function() {
         target.style = 'font-size: var(--font-size-ex);';
         assert_property_equals('font-size', unsetFontSize);
-        assert_property_equals('--font-size-ex', compute_dimension('2ex', 'unset'));
+        assert_property_equals('--font-size-ex', '');
     }, 'Lengths with ex units may not be referenced from font-size');
 
     test(function() {
         target.style = 'font-size: var(--font-size-ch);';
         assert_property_equals('font-size', unsetFontSize);
-        assert_property_equals('--font-size-ch', compute_dimension('2ch', 'unset'));
+        assert_property_equals('--font-size-ch', '');
     }, 'Lengths with ch units may not be referenced from font-size');
 
     test(function() {
@@ -120,11 +120,9 @@
 
     test(function() {
         let root = document.documentElement;
-        let expected1rem = compute_dimension('1rem', 'unset', root);
-        let expected2rem = compute_dimension('2rem', 'unset', root);
         root.style = 'font-size: var(--font-size-rem);';
-        assert_property_equals('font-size', expected1rem, root);
-        assert_property_equals('--font-size-rem', expected2rem, root);
+        assert_property_equals('font-size', unsetFontSize, root);
+        assert_property_equals('--font-size-rem', '', root);
     }, 'Lengths with rem units may not be referenced from font-size on root element');
 
     test(function() {
@@ -134,51 +132,50 @@
 
     test(function() {
         target.style = 'font-size: var(--font-size-em, 42px);';
-        assert_property_equals('font-size', '42px');
-    }, 'Fallback triggered when em unit cycle is detected');
+        assert_property_equals('font-size', unsetFontSize);
+    }, 'Fallback not triggered while inside em unit cycle');
 
     test(function() {
         target.style = 'font-size: var(--font-size-ex, 42px);';
-        assert_property_equals('font-size', '42px');
-    }, 'Fallback triggered when ex unit cycle is detected');
+        assert_property_equals('font-size', unsetFontSize);
+    }, 'Fallback not triggered while inside ex unit cycle');
 
     test(function() {
         target.style = 'font-size: var(--font-size-ch, 42px);';
-        assert_property_equals('font-size', '42px');
-    }, 'Fallback triggered when ch unit cycle is detected');
+        assert_property_equals('font-size', unsetFontSize);
+    }, 'Fallback not triggered while inside ch unit cycle');
 
     test(function() {
         let root = document.documentElement;
         root.style = 'font-size: var(--font-size-rem, 42px);';
-        assert_property_equals('font-size', '42px', root);
+        assert_property_equals('font-size', unsetFontSize, root);
         root.style = 'font-size: unset;';
-    }, 'Fallback triggered when rem unit cycle is detected on root element');
+    }, 'Fallback not triggered while inside rem unit cycle on root element');
 
     test(function() {
         target.style = 'font-size: var(--font-size-em-via-var);';
         assert_property_equals('font-size', unsetFontSize);
-        assert_property_equals('--font-size-em-via-var', compute_dimension('10em', 'unset'));
+        assert_property_equals('--font-size-em-via-var', '');
     }, 'Lengths with em units are detected via var references');
 
     test(function() {
         target.style = 'font-size: var(--font-size-ex-via-var);';
         assert_property_equals('font-size', unsetFontSize);
-        assert_property_equals('--font-size-ex-via-var', compute_dimension('10ex', 'unset'));
+        assert_property_equals('--font-size-ex-via-var', '');
     }, 'Lengths with ex units are detected via var references');
 
     test(function() {
         target.style = 'font-size: var(--font-size-ch-via-var);';
         assert_property_equals('font-size', unsetFontSize);
-        assert_property_equals('--font-size-ch-via-var', compute_dimension('10ch', 'unset'));
+        assert_property_equals('--font-size-ch-via-var', '');
     }, 'Lengths with ch units are detected via var references');
 
     test(function() {
         let root = document.documentElement;
-        let expected1rem = compute_dimension('1rem', 'unset', root);
-        let expected10rem = compute_dimension('10rem', 'unset', root);
         root.style = 'font-size: var(--font-size-rem-via-var);';
-        assert_property_equals('font-size', expected1rem, root);
-        assert_property_equals('--font-size-rem-via-var', expected10rem, root);
+        assert_property_equals('font-size', unsetFontSize, root);
+        assert_property_equals('--font-size-rem-via-var', '', root);
+        root.style = 'font-size: unset';
     }, 'Lengths with rem units are detected via var references');
 
     test(function() {