Revert of Expand scope of enable_hotwording.

chrome/browser/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/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
 import("//media/media_options.gni")
 import("//third_party/protobuf/proto_library.gni")
 
 # //build/config/android/rules.gni imports //tools/grit/grit_rule.gni, which
 # produces a conflict for the "grit" template so we have to only include one.
 if (is_android) {
   import("//build/config/android/rules.gni")
 } else {
   import("//tools/grit/grit_rule.gni")
 }
 if (is_desktop_linux) {
   import("//build/config/linux/pkg_config.gni")
 }
 
+declare_args() {
+  # 'Ok Google' hotwording is disabled by default. Set to true to enable. (This
+  # will download a closed-source NaCl module at startup.) Chrome-branded
+  # ChromeOS builds have this enabled by default.
+  enable_hotwording = is_chrome_branded && is_chromeos
+}
+
 additional_modules_list_file =
     "$root_gen_dir/chrome/browser/internal/additional_modules_list.txt"
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("../chrome_browser.gypi") ],
                           "scope",
                           [ "../chrome_browser.gypi" ])
 
 if (is_win) {
   # This is in a separate config so the flags can be applied to dependents.
@@ skipping 1333 matching lines @@
   # linking all of the test support.
   static_library("pepper_cdm_test_constants") {
     testonly = true
     visibility = [ "//chrome/*" ]
     sources = [
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }