Add `structuredClone` to the externs.
@@ -1301,6 +1301,19 @@ WindowPostMessageOptions.prototype.targetOrigin;
function postMessage(
message, targetOriginOrOptionsOrTransfer, targetOriginOrPortsOrTransfer) {}
+/**
+ * Takes the input value and returns a deep copy by performing the structured
+ * clone algorithm. Transferable objects listed in the transfer array are
+ * transferred, not just cloned, meaning that they are no longer usable in the
+ * input value.
+ * @see https://html.spec.whatwg.org/multipage/structured-data.html#structured-cloning
+ * @param {*} value
+ * @param {!StructuredSerializeOptions=} options
+ * @throws {DOMException}
+ * @return {*}
+ */
+function structuredClone(value, options) {}
+
/**
* @param {*} message
* @param {(string|!WindowPostMessageOptions)=} targetOriginOrOptions
