Added unit tests for tree_walker and automation_predicate.

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

 # Copyright 2017 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("//testing/test.gni")
 import("//chrome/test/base/js2gtest.gni")
 import("//chrome/browser/resources/chromeos/chromevox/run_jsbundler.gni")
 
 assert(is_chromeos)
@@ skipping 42 matching lines @@
 js2gtest("switch_access_webuijs_tests") {
   test_type = "webui"
   sources = [
     "auto_scan_manager_unittest.gtestjs",
     "automation_predicate_unittest.gtestjs",
     "tree_walker_unittest.gtestjs",
   ]
   extra_js_files = [
     "auto_scan_manager.js",
     "automation_predicate.js",
+    "test_support.js",
     "tree_walker.js",
   ]
   defines = [ "HAS_OUT_OF_PROC_TEST_RUNNER" ]
 }
 
 # TODO: refactor this into another file like generate_manifest.gni
 # to share with other extensions.
 template("manifest") {
   version_file = "//chrome/VERSION"
   version_script = "//build/util/version.py"
@@ skipping 25 matching lines @@
 }
 
 manifest("switch_access_manifest") {
   output_file = "$switch_access_dir/manifest.json"
 }
 
 manifest("switch_access_guest_manifest") {
   output_file = "$switch_access_dir/manifest_guest.json"
   is_guest_manifest = true
 }