Auto merge of #20482 - brainlessdeveloper:list-style-image-computed, r=emilio

Implement a URL-generic type for ListStyleImage

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This should fix the following two "expected to fail" tests described in https://github.com/servo/servo/issues/18015:

- getComputedStyle(elem) for url() listStyleImage uses the resolved URL
  and elem.style uses the original URL

- getComputedStyle(elem) for url() listStyle uses the resolved URL
  and elem.style uses the original URL

I updated the test failure expectations by removing the corresponding `.ini` file.

---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #18015 (github issue number if applicable).

<!-- Either: -->
- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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tests/unit/style/properties/serialization.rs

@@ -493,10 +493,9 @@ mod shorthand_serialization {
     }
 
     mod list_style {
-        use style::properties::longhands::list_style_image::SpecifiedValue as ListStyleImage;
         use style::properties::longhands::list_style_position::SpecifiedValue as ListStylePosition;
         use style::properties::longhands::list_style_type::SpecifiedValue as ListStyleType;
-        use style::values::Either;
+        use style::values::generics::url::UrlOrNone as ImageUrlOrNone;
         use super::*;
 
         #[test]
@@ -504,8 +503,7 @@ mod shorthand_serialization {
             let mut properties = Vec::new();
 
             let position = ListStylePosition::Inside;
-            let image =
-                ListStyleImage(Either::First(SpecifiedUrl::new_for_testing("http://servo/test.png")));
+            let image = ImageUrlOrNone::Url(SpecifiedUrl::new_for_testing("http://servo/test.png"));
             let style_type = ListStyleType::Disc;
 
             properties.push(PropertyDeclaration::ListStylePosition(position));

tests/wpt/mozilla/meta/css/get-computed-style-for-url.html.ini

@@ -1,10 +0,0 @@
-[get-computed-style-for-url.html]
-  type: testharness
-  [getComputedStyle(elem) for url() listStyle uses the resolved URL and elem.style uses the original URL]
-    expected: FAIL
-    bug: https://github.com/servo/servo/issues/18015
-
-  [getComputedStyle(elem) for url() listStyleImage uses the resolved URL and elem.style uses the original URL]
-    expected: FAIL
-    bug: https://github.com/servo/servo/issues/18015
-

tests/wpt/mozilla/tests/css/get-computed-style-for-url.html

@@ -40,6 +40,29 @@
     }, `getComputedStyle(elem) for url() ${property} uses the resolved URL and elem.style uses the original URL`);
   }
 
+  function testNoneForProperty(property) {
+    test(function() {
+      var elem = document.createElement("div");
+      elem.style[property] = "none";
+      container.appendChild(elem);
+
+      assert_equals(
+        getComputedStyle(elem)[computedPropertyName[property] || property],
+        "none"
+      );
+      assert_equals(
+        elem.style[computedPropertyName[property] || property],
+        "none"
+      );
+    }, `getComputedStyle(elem) and elem.style for url() ${property} correctly return "none"`);
+  }
+
+  testNoneForProperty("background");
+  testNoneForProperty("backgroundImage");
+  testNoneForProperty("borderImage");
+  testNoneForProperty("listStyle");
+  testNoneForProperty("listStyleImage");
+
   testUrlsForProperty("backgroundImage", "test.jpg");
   testUrlsForProperty("background", "test.jpg", "no-repeat");
   testUrlsForProperty("borderImage", "test.jpg", "30 round");