Set keys to traverse accessibility tree. Using focus ring to highlight selected node.

chrome/browser/chromeos/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//extensions/features/features.gni")
 import("//media/media_options.gni")
 import("//printing/features/features.gni")
 import("//third_party/protobuf/proto_library.gni")
@@ skipping 141 matching lines @@
     "accessibility/accessibility_extension_loader.cc",
     "accessibility/accessibility_extension_loader.h",
     "accessibility/accessibility_highlight_manager.cc",
     "accessibility/accessibility_highlight_manager.h",
     "accessibility/accessibility_manager.cc",
     "accessibility/accessibility_manager.h",
     "accessibility/accessibility_util.cc",
     "accessibility/accessibility_util.h",
     "accessibility/chromevox_panel.cc",
     "accessibility/chromevox_panel.h",
+    "accessibility/event_handler_common.cc",
+    "accessibility/event_handler_common.h",
     "accessibility/magnification_manager.cc",
     "accessibility/magnification_manager.h",
     "accessibility/select_to_speak_event_handler.cc",
     "accessibility/select_to_speak_event_handler.h",
     "accessibility/spoken_feedback_event_rewriter.cc",
     "accessibility/spoken_feedback_event_rewriter.h",
+    "accessibility/switch_access_event_handler.cc",
+    "accessibility/switch_access_event_handler.h",
     "app_mode/app_launch_utils.cc",
     "app_mode/app_launch_utils.h",
     "app_mode/app_session.cc",
     "app_mode/app_session.h",
     "app_mode/arc/arc_kiosk_app_launcher.cc",
     "app_mode/arc/arc_kiosk_app_launcher.h",
     "app_mode/arc/arc_kiosk_app_manager.cc",
     "app_mode/arc/arc_kiosk_app_manager.h",
     "app_mode/arc/arc_kiosk_app_service.cc",
     "app_mode/arc/arc_kiosk_app_service.h",
@@ skipping 1597 matching lines @@
     "policy/proto/chrome_device_policy.proto",
     "policy/proto/install_attributes.proto",
   ]
 }
 
 proto_library("attestation_proto") {
   sources = [
     "attestation/attestation_key_payload.proto",
   ]
 }