Use new earcons in ChromeVox Next.

chrome/browser/resources/chromeos/chromevox/chromevox.gni

 # 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.
 # Common variables shared amongst all ChromeVox targets.
 
 assert(is_chromeos)
 
 # TODO(plundblad): Move the below variables to BUILD.gn when crbug.com/395883
 # is resolved.
 
@@ skipping 110 matching lines @@
   "common/traverse_math.js",
   "common/traverse_table.js",
   "common/traverse_util.js",
   "common/xpath_util.js",
   "cvox2/background/automation_predicate.js",
   "cvox2/background/automation_util.js",
   "cvox2/background/background.js",
   "cvox2/background/classic_compatibility.js",
   "cvox2/background/cursors.js",
   "cvox2/background/earcon_engine.js",
+  "cvox2/background/next_earcons.js",
   "cvox2/background/output.js",
   "extensions/searchvox/abstract_result.js",
   "extensions/searchvox/constants.js",
   "extensions/searchvox/context_menu.js",
   "extensions/searchvox/loader.js",
   "extensions/searchvox/results.js",
   "extensions/searchvox/search.js",
   "extensions/searchvox/search_tools.js",
   "extensions/searchvox/util.js",
   "host/chrome/braille.js",
   "host/chrome/braille_background.js",
+  "host/chrome/classic_earcons.js",
   "host/chrome/earcons.js",
-  "host/chrome/earcons_background.js",
   "host/chrome/extension_bridge.js",
   "host/chrome/host.js",
   "host/chrome/mathjax.js",
   "host/chrome/tts.js",
   "host/chrome/tts_background.js",
   "host/chrome/tts_base.js",
   "host/interface/abstract_earcons.js",
   "host/interface/abstract_host.js",
   "host/interface/abstract_mathjax.js",
   "host/interface/abstract_tts.js",
@@ skipping 40 matching lines @@
   "string/string.js",
   "dom/nodetype.js",
   "base.js",
   "asserts/asserts.js",
   "debug/error.js",
   "object/object.js",
 ]
 
 closure_library_modules =
     rebase_path(relative_closure_library_modules, ".", closure_library_dir)