Move enable_app_list to a buildflag.

chrome/browser/resources/chromeos/chromevox/BUILD.gn

 # Copyright 2015 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.
 
 import("//build/config/features.gni")
+import("//chrome/common/features.gni")
 import("//testing/test.gni")
 import("//chrome/test/base/js2gtest.gni")
 import("run_jsbundler.gni")
 
 assert(is_chromeos)
 
 declare_args() {
   # Whether to compress the main Chromevox javascript files or load the
   # modules individually from source files.
   chromevox_compress_js = !is_debug
@@ skipping 664 matching lines @@
   ]
   gen_include_files = [
     "testing/assert_additions.js",
     "testing/callback_helper.js",
     "testing/chromevox_e2e_test_base.js",
     "testing/chromevox_next_e2e_test_base.js",
     "testing/mock_feedback.js",
   ]
   defines = [ "HAS_OUT_OF_PROC_TEST_RUNNER" ]
 }