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

chrome/browser/resources/chromeos/chromevox/chromevox_tests.gypi

 # 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.
 
 {
   'includes': [
     '../../../../js_unittest_vars.gypi',
   ],
   'variables': {
     'chromevox_test_deps_js_file': '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/resources/chromeos/chromevox/test_deps.js',
@@ skipping 124 matching lines @@
         'common/editable_text_area_shadow_test.unitjs',
         'common/editable_text_test.unitjs',
         'common/find_util_test.unitjs',
         'common/key_sequence_test.unitjs',
         'common/math_semantic_tree_test.unitjs',
         'common/page_selection_test.unitjs',
         'common/selection_util_test.unitjs',
         'common/spannable_test.unitjs',
         'chromevox/injected/event_watcher_test.unitjs',
         'chromevox/injected/live_regions_test.unitjs',
+        'cvox2/background/background.extjs',
         'host/chrome/braille_display_manager_test.unitjs',
         'host/chrome/braille_input_handler_test.unitjs',
         'host/chrome/braille_integration_test.unitjs',
         'host/chrome/braille_table_test.extjs',
         'host/chrome/expanding_braille_translator_test.unitjs',
         'host/chrome/tts_background_test.extjs',
         'liblouis_nacl/liblouis_test.extjs',
         'walkers/character_walker_test.unitjs',
         'walkers/group_walker_test.unitjs',
         'walkers/object_walker_test.unitjs',
         'walkers/layout_line_walker_test.unitjs',
         'walkers/math_shifter_test.unitjs',
         'walkers/sentence_walker_test.unitjs',
         'walkers/structural_line_walker_test.unitjs',
         'walkers/table_walker_test.unitjs',
         'walkers/word_walker_test.unitjs',
       ],
-      'conditions': [
-        ['use_chromevox_next==1', {
-          'sources': ['../chromevox2/cvox2/background/background.extjs'],
-        }],
-      ],
     },  # target chromevox_tests
     {
       'target_name': 'chromevox_test_messages_js',
       'type': 'none',
       'actions': [
         {
           'action_name': 'test_messages_js',
           'message': 'Generate <(_target_name)',
           'variables': {
             'english_messages_file': '<(chromevox_dest_dir)/_locales/en/messages.json',
@@ skipping 47 matching lines @@
             '<@(js_files)',
           ],
         },
       ],
       'dependencies': [
         'chromevox_test_messages_js',
       ],
     },  # target chromevox_test_deps_js
   ],
 }