Bug 1898468 - When converting legacy rgb(..) to color(srgb ..), ensure the flags are set accordingly r=layout-reviewers,emilio

Differential Revision: https://phabricator.services.mozilla.com/D211341

servo/components/style/color/parsing.rs

@@ -425,9 +425,13 @@ fn parse_color_with_color_space<'i, 't>(
     let color_space = PredefinedColorSpace::parse(arguments)?;
     let component_parser = ComponentParser {
         context: component_parser.context,
-        origin_color: component_parser
-            .origin_color
-            .map(|c| c.to_color_space(ColorSpace::from(color_space))),
+        origin_color: component_parser.origin_color.map(|c| {
+            // If the origin color was in legacy srgb, converting it won't
+            // change it to modern syntax. So make sure it's in modern syntax.
+            let mut c = c.to_color_space(ColorSpace::from(color_space));
+            c.flags.remove(ColorFlags::IS_LEGACY_SRGB);
+            c
+        }),
     };
 
     let c1 = component_parser.parse_number_or_percentage(arguments, true)?;

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

@@ -763,6 +763,10 @@
     fuzzy_test_valid_color(`lch(from var(--mycolor) l 0 h)`);
     fuzzy_test_valid_color(`var(--mygray)`);
     fuzzy_test_valid_color(`lch(from var(--mygray) l 30 h)`);
+
+    // Ensure that converting between legacy and modern sRGB color spaces work as expected.
+    fuzzy_test_valid_color(`color(from rebeccapurple srgb r g b)`, `color(srgb 0.4 0.2 0.6)`, 0.01);
+    fuzzy_test_valid_color(`rgb(from color(srgb 0.4 0.2 0.6) r g b)`, `color(srgb 0.4 0.2 0.6)`, 0.01);
 </script>
 </body>
 </html>