Merge pull request #13948 from Snuffleupagus/structuredClone

Use the native `structuredClone` implementation when it's available

src/display/api.js

@@ -1899,13 +1899,21 @@ class PDFPageProxy {
 class LoopbackPort {
   constructor() {
     this._listeners = [];
-    this._deferred = Promise.resolve(undefined);
+    this._deferred = Promise.resolve();
   }
 
   postMessage(obj, transfers) {
-    function cloneValue(value) {
+    function cloneValue(object) {
+      if (
+        (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
+        globalThis.structuredClone
+      ) {
+        return globalThis.structuredClone(object, transfers);
+      }
+
       // Trying to perform a structured clone close to the spec, including
       // transfers.
+      function fallbackCloneValue(value) {
         if (
           typeof value === "function" ||
           typeof value === "symbol" ||
@@ -1942,7 +1950,7 @@ class LoopbackPort {
           result = new Map();
           cloned.set(value, result); // Adding to cache now for cyclic references.
           for (const [key, val] of value) {
-          result.set(key, cloneValue(val));
+            result.set(key, fallbackCloneValue(val));
           }
           return result;
         }
@@ -1950,7 +1958,7 @@ class LoopbackPort {
           result = new Set();
           cloned.set(value, result); // Adding to cache now for cyclic references.
           for (const val of value) {
-          result.add(cloneValue(val));
+            result.add(fallbackCloneValue(val));
           }
           return result;
         }
@@ -1970,12 +1978,15 @@ class LoopbackPort {
           if (typeof desc.value === "function" && !value.hasOwnProperty?.(i)) {
             continue;
           }
-        result[i] = cloneValue(desc.value);
+          result[i] = fallbackCloneValue(desc.value);
         }
         return result;
       }
 
       const cloned = new WeakMap();
+      return fallbackCloneValue(object);
+    }
+
     const event = { data: cloneValue(obj) };
 
     this._deferred.then(() => {