Update references to the extension messaging APIs to point to the "runtime"

chrome/common/extensions/docs/examples/api/infobars/sandwichbar/contentscript.js

 /*
  * Copyright (c) 2010 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 regex = /sandwich/gi;
 matches = document.body.innerText.match(regex);
 if (matches) {
   var payload = {
     count: matches.length    // Pass the number of matches back.
   };
   chrome.extension.sendRequest(payload, function(response) {});
-}
+}