Full x-load checks Chromium support.

Author: hackademix

src/content/eventsHook.main.js

@@ -24,17 +24,61 @@ if (location.protocol == "file:") {
   const {exportFunction, patchWindow} = Worlds.main;
 
   function modifyWindow(scope, {port, xray}) {
-    const {window} = xray;
+    const { window } = xray;
+    const { Proxy, document } = window;
+
+    const { Reflect } = globalThis;
 
-    const { Proxy } = window;
     const { addEventListener } = window.EventTarget.prototype;
+    const nodeProps = {};
+    for (const prop of ["ownerDocument", "parentNode", "nextSibling"]) {
+      nodeProps[prop] = xray.getSafeDescriptor(Node.prototype, prop, "get").get;
+    }
+    for (const method of ["insertBefore", "removeChild"]) {
+      nodeProps[method] = Node.prototype[method];
+    }
+    const adoptNode = document.adoptNode;
+    const getDocumentElement = xray.getSafeDescriptor(Document.prototype, "documentElement", "get").get;
 
     const watchList = new WeakSet();
 
+    const NO_ARGS = [];
+    const call = (func, obj, ...args) => Reflect.apply(func, obj, args || NO_ARGS);
+
     const watch = watching => {
       if (!watchList.has(watching)) {
-        port.postMessage({watching});
-        watchList.add(watching);
+        const ownerDocument =  call(nodeProps.ownerDocument, watching);
+        const crossDoc = ownerDocument != document;
+        const parentNode = call(nodeProps.parentNode, watching);
+
+        if (!crossDoc && parentNode) {
+          // Nothing to do: eventHook.js' MutationObserver should kick in
+          return;
+        }
+
+        if (xray.enabled) {
+          port.postMessage({watching});
+          watchList.add(watching);
+          return;
+        }
+
+        // Chromium cannot marshall DOM nodes in port.postMessage():
+        // following hack triggers eventHook.js' mutation observer instead.
+
+        const nextSibling = call(nodeProps.nextSibling, watching);
+        if (crossDoc) {
+          call(adoptNode, document, watching);
+        }
+        const documentElement = call(getDocumentElement, document);
+        call(nodeProps.insertBefore, documentElement, watching, null);
+        call(nodeProps.removeChild, documentElement, watching);
+        if (crossDoc) {
+          // put the node back at its place in its document
+          call(adoptNode, ownerDocument, watching);
+          if (parentNode) {
+            call(nodeProps.insertBefore, ownerDocument,  watching, nextSibling);
+          }
+        }
       }
     }