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

chrome/browser/resources/chromeos/chromevox2/chromevox.gyp

-# 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.
-
-{
-  'conditions': [
-    ['chromeos==1 and disable_nacl==0 and disable_nacl_untrusted==0', {
-      'includes': [ '../chromevox/common.gypi', ],
-      'targets': [
-        {
-          'target_name': 'chromevox2',
-          'type': 'none',
-          'dependencies': [
-            'chromevox2_copied_scripts',
-            'chromevox2_deps',
-            'chromevox2_manifest',
-            'chromevox2_guest_manifest',
-            'chromevox2_resources',
-            '../chromevox/chromevox.gyp:chromevox_resources',
-          ],
-        },
-        {
-          'target_name': 'chromevox2_copied_scripts',
-          'type': 'none',
-          'variables': {
-            'dest_dir': '<(chromevox_dest_dir)',
-          },
-          'sources': [
-            'cvox2/background/loader.js',
-          ],
-          'includes': [ '../chromevox/copy_js.gypi', ],
-        },
-        {
-          'target_name': 'chromevox2_deps',
-          'type': 'none',
-          'variables': {
-            'deps_js_output_file': '<(chromevox_dest_dir)/deps.js',
-          },
-          'sources': [
-            'cvox2/background/loader.js',
-          ],
-          'includes': ['../chromevox/generate_deps.gypi'],
-        },
-        {
-          'target_name': 'chromevox2_resources',
-          'type': 'none',
-          'copies': [
-            {
-              'destination': '<(PRODUCT_DIR)/resources/chromeos/chromevox/cvox2/background',
-              'files': [
-                'cvox2/background/background.html',
-              ],
-            },
-          ],
-        },
-        {
-          'target_name': 'chromevox2_manifest',
-          'type': 'none',
-          'variables': {
-            'output_manifest_path': '<(chromevox_dest_dir)/manifest.json'
-          },
-          'includes': [ '../chromevox/generate_manifest.gypi', ],
-        },
-        {
-          'target_name': 'chromevox2_guest_manifest',
-          'type': 'none',
-          'variables': {
-            'output_manifest_path': '<(chromevox_dest_dir)/manifest_guest.json',
-            'is_guest_manifest': 1,
-          },
-          'includes': [ '../chromevox/generate_manifest.gypi', ],
-        },
-      ],
-    }],
-  ],
-}