fix(geometry): expose WebKitCSSMatrix alias

moli-benchmark/wpt-cross-current/failed-cases.txt

@@ -2469,7 +2469,6 @@ css/cssom/getComputedStyle-insets-sticky.html
 css/cssom/getComputedStyle-layout-dependent-replaced-into-ib-split.html
 css/cssom/idlharness.html
 css/cssom/style-sheet-interfaces-001.html
-css/geometry/DOMMatrix-stringifier.html
 css/geometry/DOMMatrix2DInit-validate-fixup.html
 css/geometry/DOMQuad-001.html
 css/geometry/DOMQuad-002.html

moli-benchmark/wpt-cross-current/passed-cases.txt

@@ -3349,6 +3349,7 @@ css/geometry/DOMMatrix-invert-non-invertible.html
 css/geometry/DOMMatrix-invert-preserves-2d.html
 css/geometry/DOMMatrix-invertSelf.html
 css/geometry/DOMMatrix-newobject.html
+css/geometry/DOMMatrix-stringifier.html
 css/geometry/DOMMatrixInit-validate-fixup.html
 css/geometry/DOMPoint-001.html
 css/geometry/DOMPoint-002.html

moli-renderer-v8/src/script_vm/tests/browser_api/misc.rs

@@ -5730,6 +5730,32 @@ fn dom_point_matrix_transform_validates_matrix_init_and_returns_in_the_function_
     );
 }
 
+#[test]
+fn dom_matrix_exposes_webkit_css_matrix_alias() {
+    let mut vm = new_storage_test_vm("https://dommatrix-webkit-alias.test/");
+
+    let result = vm
+        .eval(
+            r#"
+(() => {
+  const webkitDescriptor = Object.getOwnPropertyDescriptor(globalThis, "WebKitCSSMatrix");
+  const matrix = new WebKitCSSMatrix();
+  return [
+    WebKitCSSMatrix === DOMMatrix,
+    WebKitCSSMatrix.prototype === DOMMatrix.prototype,
+    WebKitCSSMatrix.name,
+    matrix instanceof DOMMatrix,
+    matrix instanceof DOMMatrixReadOnly,
+    [webkitDescriptor.writable, webkitDescriptor.enumerable, webkitDescriptor.configurable].join(",")
+  ].join("|");
+})()
+"#,
+        )
+        .expect("DOMMatrix legacy Window aliases should evaluate");
+
+    assert_eq!(result, "true|true|DOMMatrix|true|true|true,false,true");
+}
+
 #[test]
 fn dom_matrix_objects_keep_declared_brand_and_own_slots() {
     let mut vm = new_storage_test_vm("https://dommatrix-declared-slots.test/");