Create GN build step for transform_additional_modules_list.py.

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/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//components/nacl/nacl_defines.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.
@@ skipping 662 matching lines @@
   # "depfile" in GN).
   outputs = [ about_credits_file ]
 
   args = [
     "credits",
     rebase_path(about_credits_file, root_build_dir),
   ]
 }
 
 # GYP version: chrome/chrome_resource.gyp:chrome_internal_resources_gen
-# TODO(GYP) write internal action
-if (false) {  #if (is_chrome_branded) {
+if (is_chrome_branded) {
   action("chrome_internal_resources_gen") {
-    # TODO(GYP)
+    script = "internal/transform_additional_modules_list.py"
+    sources = [ "internal/resources/additional_modules_list.input" ]
+    outputs = [ additional_modules_list_file ]
+    args = rebase_path(sources, root_build_dir) +
+           rebase_path(outputs, root_build_dir)
   }
 } else {
   group("chrome_internal_resources_gen") {
     # Empty placeholder.
   }
 }
 
 # In GYP this is part of test_support_common.
 source_set("test_support") {
   testonly = true
@@ skipping 231 matching lines @@
     ]
   }
 
   if (enable_wifi_bootstrapping) {
     sources += [
       "local_discovery/wifi/mock_wifi_manager.cc",
       "local_discovery/wifi/mock_wifi_manager.h",
     ]
   }
 }