Enable runtime switching between ChromeVox and ChromeVox next via command line.

chrome/browser/resources/chromeos/chromevox2/cvox2/injected/injected.js

-// Copyright 2014 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.
-
-/**
- * @fileoverview The entry point for all ChromeVox2 related code for the
- * injected content script.
- * This script will temporarily forward any events we need during the
- * ChromeVox/ChromeVox2 timeframe where extension APIs do not exist (e.g.
- * keyboard events).
- */
-
-goog.provide('cvox2.Injected');
-
-var port = chrome.extension.connect({name: 'chromevox2'});
-document.body.addEventListener('keydown', function(evt) {
-  port.postMessage({keydown: evt.keyCode});
-}, true);