GTTF: convert some tests in chrome to use EmbeddedTestServer patch nr 1

chrome/test/data/extensions/api_test/content_scripts/extension_process/background.js

 // Copyright (c) 2011 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 numPings = 0;
 chrome.extension.onRequest.addListener(function(data) {
   if (data != "ping")
     chrome.test.fail("Unexpected request: " + JSON.stringify(data));
 
   if (++numPings == 2)
     chrome.test.notifyPass();
 });
 
 chrome.test.getConfig(function(config) {
-  var test_file_url = "http://localhost:PORT/files/extensions/test_file.html"
+  var test_file_url = "http://localhost:PORT/extensions/test_file.html"
       .replace(/PORT/, config.testServer.port);
 
   // Add a window.
   var w = window.open(test_file_url);
 
   // Add an iframe.
   var iframe = document.createElement("iframe");
   iframe.src = test_file_url;
   document.getElementById("iframeContainer").appendChild(iframe);
 });