Remove hotword installation code at compile time if hotwording disabled.

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 427c7255974368dae94949a9409f84aaed12d30c..85ed0463fd95a23524b36effc3ff1c5c08e68407 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -21,13 +21,6 @@ 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"
 
@@ -566,10 +559,6 @@ source_set("browser") {
     }
   }
 
-  if (enable_hotwording) {
-    defines += [ "ENABLE_HOTWORDING" ]
-  }
-
   if (is_linux) {
     deps += [ "//device/media_transfer_protocol" ]
   }