Refactor the implementation of the webNavigation extension API.

chrome/test/data/extensions/api_test/webnavigation/download/test_download.js

 // Copyright 2013 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.
 
 onload = function() {
   var getURL = chrome.extension.getURL;
   chrome.tabs.create({"url": "about:blank"}, function(tab) {
     var tabId = tab.id;
     chrome.test.getConfig(function(config) {
       chrome.test.runTests([
         // Navigates to a page that redirects (on the server side) to a.html.
         function serverRedirect() {
           expect([
             { label: "a-onBeforeNavigate",
               event: "onBeforeNavigate",
               details: { frameId: 0,
                          parentFrameId: -1,
-                         processId: 0,
+                         processId: -1,
                          tabId: 0,
                          timeStamp: 0,
                          url: getURL('a.html') }},
             { label: "a-onCommitted",
               event: "onCommitted",
               details: { frameId: 0,
                          processId: 0,
                          tabId: 0,
                          timeStamp: 0,
                          transitionQualifiers: [],
@@ skipping 14 matching lines @@
                          timeStamp: 0,
                          url: getURL('a.html') }}],
           [ navigationOrder("a-") ]);
           chrome.tabs.update(
               tabId, { url: getURL('a.html?' + config.testServer.port) });
         },
       ]);
     });
   });
 };