Added unit tests for auto_scan_manager. Created switch access test target.

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 23 matching lines @@
     "prefs.js",
     "switch_access.js",
     "tree_walker.js",
   ]
   rewrite_rules = [
     rebase_path(".", root_build_dir) + ":",
     rebase_path(closure_library_dir, root_build_dir) + ":closure",
   ]
 }
 
+test("switch_access_tests") {
+  deps = [
+    ":switch_access_webuijs_tests",
+    "//chrome/test:browser_tests_runner",
+  ]
+}
+
+js2gtest("switch_access_webuijs_tests") {
+  test_type = "webui"
+  sources = [
+    "auto_scan_manager_unittest.gtestjs",
+    "tree_walker_unittest.gtestjs",
+  ]
+  extra_js_files = [
+    "auto_scan_manager.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"
   template_file = "manifest.json.jinja2"
   output_file = invoker.output_file
   key = "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"
   action(target_name) {
     script = "//chrome/browser/resources/chromeos/chromevox/tools/generate_manifest.py"
@@ skipping 20 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
 }