Refresh ChromeVox options page CSS

chrome/third_party/chromevox/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.
 
 assert(is_chromeos)
 
 chromevox_out_dir = "$root_out_dir/resources/chromeos/chromevox"
 
 group("chromevox_third_party_resources") {
   deps = [
-    ":chromevox_third_party_background_resources",
     ":chromevox_third_party_injected_resources",
   ]
 }
 
-copy("chromevox_third_party_background_resources") {
-  sources = [
-    "chromevox/background/chrome_shared2.css",
-    "chromevox/background/options.css",
-    "chromevox/background/options_widgets.css",
-  ]
-  outputs = [
-    "$chromevox_out_dir/chromevox/background/{{source_file_part}}",
-  ]
-}
-
 copy("chromevox_third_party_injected_resources") {
   sources = [
     "chromevox/injected/mathjax.js",
     "chromevox/injected/mathjax_external_util.js",
   ]
   outputs = [
     "$chromevox_out_dir/chromevox/injected/{{source_file_part}}",
   ]
 }