[wasm] Support wasm module structured cloning.

chrome/test/data/wasm/wasm_tests.js

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Utility function. Use this to return data back to the C++ test.
+function respondToTestHarness(data) {
+  if (!window.domAutomationController) {
+    console.log("ERROR: no automation controller available");
+    return;
+  }
+  window.domAutomationController.send(data);
+}
+
+function test_instantiateInWorker() {
+  fetch('incrementer.wasm')
+      .then(response => {
+        if (!response.ok) throw new Error(response.statusText);
+        return response.arrayBuffer();
+      })
+      .then(data => {
+        var mod = new WebAssembly.Module(data);
+        var worker = new Worker("wasm_serialization_worker.js");
+        worker.postMessage(mod);
+        worker.onmessage = function(event) {
+          respondToTestHarness(event.data);
+        }
+      })
+      .catch(error => respondToTestHarness(error.message));
+}