Refactor the implementation of the webNavigation extension API.

chrome/test/data/extensions/api_test/webnavigation/crossProcessHistory/framework.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.
 
 var deepEq = chrome.test.checkDeepEq;
 var expectedEventData;
 var expectedEventOrder;
 var capturedEventData;
 var nextFrameId;
 var frameIds;
@@ skipping 34 matching lines @@
 //     event with label "a" needs to occur before event with label "b". The
 //     relative order of "a" and "d" does not matter.
 function expect(data, order) {
   expectedEventData = data;
   capturedEventData = [];
   expectedEventOrder = order;
   nextFrameId = 1;
   frameIds = {};
   nextTabId = 0;
   tabIds = {};
-  nextProcessId = 0;
+  nextProcessId = -1;
   processIds = {}
   initListeners();
 }
 
 function checkExpectations() {
   if (capturedEventData.length < expectedEventData.length) {
     return;
   }
   if (capturedEventData.length > expectedEventData.length) {
     chrome.test.fail("Recorded too many events. " +
@@ skipping 188 matching lines @@
   return [ main_frame + "onCommitted",
            iframe + "onBeforeNavigate",
            iframe + "onCompleted",
            main_frame + "onCompleted" ];
 }
 
 // Returns the constraint expressing that a frame was loaded by another.
 function isLoadedBy(target, source) {
   return [ source + "onDOMContentLoaded", target + "onBeforeNavigate"];
 }