LibWeb: Implement HTMLImageElement.crossOrigin

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

@@ -26,3 +26,10 @@ 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
+img crossOrigin initial value: null
+img crossOrigin value after setting to "invalid": anonymous
+img crossOrigin value after setting to "use-credentials": use-credentials
+img crossOrigin value after setting to null: null
+img crossOrigin value after setting to "USE-CREDENTIALS": use-credentials
+img crossOrigin value after setting to "": anonymous
+img 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", "link"]) {
+        for (let elementName of ["audio", "script", "video", "link", "img"]) {
           const element = document.createElement(elementName);
           println(`${elementName} crossOrigin initial value: ${element.crossOrigin}`);
           element.crossOrigin = "invalid";

Userland/Libraries/LibWeb/HTML/HTMLImageElement.idl

@@ -11,7 +11,7 @@ interface HTMLImageElement : HTMLElement {
     [CEReactions, Reflect] attribute DOMString src;
     [CEReactions, Reflect] attribute DOMString srcset;
     [CEReactions, Reflect] attribute DOMString sizes;
-    [FIXME, CEReactions] attribute DOMString? crossOrigin;
+    [CEReactions, Enumerated=CORSSettingsAttribute, Reflect=crossorigin] attribute DOMString? crossOrigin;
     [CEReactions, Reflect=usemap] attribute DOMString useMap;
     [CEReactions, Reflect=ismap] attribute boolean isMap;
     [CEReactions] attribute unsigned long width;