[CSS] @font-palette-values override-colors accepts only absolute color

LayoutTests/TestExpectations

@@ -7431,7 +7431,3 @@ webkit.org/b/272417 imported/w3c/web-platform-tests/svg/path/property/priority.s
 
 # re-import css/css-align WPT failure
 webkit.org/b/271692 imported/w3c/web-platform-tests/css/css-align/blocks/align-content-block-break-overflow-020.html [ ImageOnlyFailure ]
-
-# re-import css/css-fonts/parsing crash. Skip until https://bugs.webkit.org/show_bug.cgi?id=273888 is fixed
-webkit.org/b/273888 imported/w3c/web-platform-tests/css/css-fonts/parsing/font-palette-values-invalid.html [ Skip ]
-webkit.org/b/273888 imported/w3c/web-platform-tests/css/css-fonts/parsing/font-palette-values-valid.html [ Skip ]

LayoutTests/imported/w3c/web-platform-tests/css/css-fonts/parsing/font-palette-values-invalid-expected.txt

@@ -21,7 +21,7 @@ PASS CSS Fonts Module Level 4: parsing @font-palette-values 18
 PASS CSS Fonts Module Level 4: parsing @font-palette-values 19
 PASS CSS Fonts Module Level 4: parsing @font-palette-values 20
 PASS CSS Fonts Module Level 4: parsing @font-palette-values 21
-FAIL CSS Fonts Module Level 4: parsing @font-palette-values 22 assert_equals: expected -1 but got 27
+PASS CSS Fonts Module Level 4: parsing @font-palette-values 22
 PASS CSS Fonts Module Level 4: parsing @font-palette-values 23
 PASS CSS Fonts Module Level 4: parsing @font-palette-values 24
 

LayoutTests/imported/w3c/web-platform-tests/css/css-fonts/parsing/font-palette-values-valid-expected.txt

@@ -32,5 +32,5 @@ PASS CSS Fonts Module Level 4: parsing @font-palette-values 29
 PASS CSS Fonts Module Level 4: parsing @font-palette-values 30
 PASS CSS Fonts Module Level 4: parsing @font-palette-values 31
 PASS CSS Fonts Module Level 4: parsing @font-palette-values 32
-FAIL CSS Fonts Module Level 4: parsing @font-palette-values 33 assert_equals: expected "0 color-mix(in lch, red, blue)" but got "0 rgba(0, 0, 0, 0)"
+FAIL CSS Fonts Module Level 4: parsing @font-palette-values 33 assert_equals: expected "0 color-mix(in lch, red, blue)" but got ""
 

Source/WebCore/css/CSSPrimitiveValue.cpp

@@ -313,6 +313,21 @@ CSSPrimitiveValue::CSSPrimitiveValue(Color color)
     new (reinterpret_cast<Color*>(&m_value.colorAsInteger)) Color(WTFMove(color));
 }
 
+Color CSSPrimitiveValue::absoluteColor() const
+{
+    if (isColor())
+        return color();
+
+    // FIXME: there are some cases where we can resolve a dynamic color at parse time, we should support them.
+    if (isUnresolvedColor())
+        return { };
+
+    if (StyleColor::isAbsoluteColorKeyword(valueID()))
+        return StyleColor::colorFromAbsoluteKeyword(valueID());
+
+    return { };
+}
+
 CSSPrimitiveValue::CSSPrimitiveValue(StaticCSSValueTag, CSSValueID valueID)
     : CSSValue(PrimitiveClass)
 {

Source/WebCore/css/CSSPrimitiveValue.h

@@ -125,6 +125,10 @@ class CSSPrimitiveValue final : public CSSValue {
     bool isColor() const { return primitiveUnitType() == CSSUnitType::CSS_RGBCOLOR; }
     const Color& color() const { ASSERT(isColor()); return *reinterpret_cast<const Color*>(&m_value.colorAsInteger); }
 
+    // Return an absolute color if possible, otherwise an invalid color.
+    // https://drafts.csswg.org/css-color-5/#absolute-color
+    Color absoluteColor() const;
+
     static Ref<CSSPrimitiveValue> createCustomIdent(String);
     bool isCustomIdent() const { return primitiveUnitType() == CSSUnitType::CustomIdent; }
 

Source/WebCore/css/parser/CSSParserImpl.cpp

@@ -927,7 +927,10 @@ RefPtr<StyleRuleFontPaletteValues> CSSParserImpl::consumeFontPaletteValuesRule(C
             if (!pair.key().isInteger())
                 continue;
             unsigned key = pair.key().value<unsigned>();
-            Color color = pair.color().isColor() ? pair.color().color() : StyleColor::colorFromKeyword(pair.color().valueID(), { });
+            auto color = pair.color().absoluteColor();
+            // Ignore non absolute color https://drafts.csswg.org/css-fonts/#override-color
+            if (!color.isValid())
+                continue;
             overrideColors.append(std::make_pair(key, color));
         }
     }