Basic tests for sending messages over a navigator.connect initiated channel.

LayoutTests/http/tests/navigatorconnect/resources/test-helpers.js

+// Helper method that waits for a {success: <boolean>, result: any} reply on
+// a port and returns a promise that resolves (if success is true) or rejects
+// the promise with the value of the result attribute.
+function reply_as_promise(t, port) {
+  return new Promise(function(resolve, reject) {
+      var got_reply = false;
+      port.onmessage = t.step_func(function(event) {
+        assert_false(got_reply);
+        assert_true('success' in event.data);
+        assert_true('result' in event.data);
+        got_reply = true;
+        if (event.data.success)
+          resolve(event.data.result);
+        else
+          reject(event.data.result);
+      });
+    });
+}
+
+// Method that behaves similarly to navigator.connect, but the actual connect
+// call is made from a cross origin iframe.
+function cross_origin_connect(t, service) {
+  // |service| is a relative URL, but for this to work from the iframe it needs
+  // an absolute URL.
+  var target_url = location.origin + base_path() + service;
+  return with_iframe(
+      cross_origin + base_path() + 'resources/connect-helper.html')
+    .then(function(iframe) {
+        var channel = new MessageChannel();
+        iframe.contentWindow.postMessage(
+          {connect: target_url, port: channel.port2}, '*', [channel.port2]);
+        return reply_as_promise(t, channel.port1);
+    });
+}
+
+// Method that behaves similarly to navigator.connect, but the actual connect
+// call is made from a worker.
+function connect_from_worker(t, service) {
+  // |service| is a relative URL, but for this to work from the worker it needs
+  // an absolute URL.
+  var target_url = location.origin + base_path() + service;
+  var worker = new Worker('resources/connect-helper.js');
+  var channel = new MessageChannel();
+  worker.postMessage
+    ({connect: target_url, port: channel.port2}, [channel.port2]);
+  return reply_as_promise(t, channel.port1);
+}