Require manifests for native messaging hosts.

chrome/common/extensions/docs/examples/extensions/native_messaging/popup.js

 // Copyright (c) 2012 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.
 
 var port = null;
 
 function gotNativeMessage(message) {
   document.getElementById('response').innerHTML = "<p>Message Number: " +
                                                   message.id +
                                                   "</p><p>Message Text: " +
                                                   JSON.stringify(message.echo) +
                                                   "</p>";
 }
 
 function sendNativeMessage() {
   if (!port) {
-    app = navigator.platform.match(/win/i) ? 'echo.bat' : 'echo.py';
-    port = chrome.extension.connectNative(app);
+    port = chrome.extension.connectNative('com.google.chrome.test.echo');
     port.onMessage.addListener(gotNativeMessage);
     document.getElementById('input-text').style.display = 'block';
     document.getElementById('send-native-message').innerHTML = 'Send Message';
   }
 
   port.postMessage({"message": document.getElementById('input-text').value});
 }
 
 document.addEventListener('DOMContentLoaded', function () {
   document.getElementById('input-text').style.display = 'none';
   document.getElementById('send-native-message').addEventListener(
       'click', sendNativeMessage);
 });