LibWeb: Implement HTMLLinkElement.crossOrigin

Author: https://github.com/jamierocks
Commit: https://github.com/LadybirdBrowser/ladybird/commit/d7d60268ec
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/24
Reviewed-by: https://github.com/tcl3 ✅

Tests/LibWeb/Text/expected/HTML/crossOrigin-attribute.txt

@@ -19,3 +19,10 @@ video crossOrigin value after setting to null: null
 video crossOrigin value after setting to "USE-CREDENTIALS": use-credentials
 video crossOrigin value after setting to "": anonymous
 video crossOrigin value after calling removeAttribute: null
+link crossOrigin initial value: null
+link crossOrigin value after setting to "invalid": anonymous
+link crossOrigin value after setting to "use-credentials": use-credentials
+link crossOrigin value after setting to null: null
+link crossOrigin value after setting to "USE-CREDENTIALS": use-credentials
+link crossOrigin value after setting to "": anonymous
+link crossOrigin value after calling removeAttribute: null

Tests/LibWeb/Text/input/HTML/crossOrigin-attribute.html

@@ -2,7 +2,7 @@
 <script src="../include.js"></script>
 <script>
     test(() => {
-        for (let elementName of ["audio", "script", "video"]) {
+        for (let elementName of ["audio", "script", "video", "link"]) {
           const element = document.createElement(elementName);
           println(`${elementName} crossOrigin initial value: ${element.crossOrigin}`);
           element.crossOrigin = "invalid";

Userland/Libraries/LibWeb/HTML/HTMLLinkElement.idl

@@ -9,7 +9,7 @@ interface HTMLLinkElement : HTMLElement {
     [HTMLConstructor] constructor();
 
     [CEReactions, Reflect] attribute DOMString href;
-    [FIXME, CEReactions] attribute DOMString? crossOrigin;
+    [CEReactions, Reflect=crossorigin, Enumerated=CORSSettingsAttribute] attribute DOMString? crossOrigin;
     [CEReactions, Reflect] attribute DOMString rel;
     [FIXME, CEReactions] attribute DOMString as;
     [SameObject, PutForwards=value] readonly attribute DOMTokenList relList;