Files app: JS module for app_util.js

Bug: 1133186
Change-Id: Id8fcad0765660cf8ad4c4d57ebd61c70ec3885e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2500690Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821147}

ui/file_manager/base/js/BUILD.gn

@@ -5,18 +5,25 @@
 import("//third_party/closure_compiler/compile_js.gni")
 import("//third_party/closure_compiler/js_unit_tests.gni")
 import("//ui/file_manager/base/gn/js_test_gen_html.gni")
+import("//ui/webui/resources/tools/js_modulizer.gni")
 
 visibility = [ "//ui/file_manager/*" ]
 
 group("closure_compile") {
   testonly = true
   deps = [
+    ":closure_compile_jsmodules",
     ":closure_compile_module",
     ":js_test_gen_html_type_check_auto",
     ":test_support_type_check",
   ]
 }
 
+js_type_check("closure_compile_jsmodules") {
+  uses_js_modules = true
+  deps = [ ":app_util.m" ]
+}
+
 js_type_check("closure_compile_module") {
   deps = [
     ":app_util",
@@ -37,6 +44,14 @@ js_library("app_util") {
   externs_list = [ "//ui/file_manager/externs/app_window_common.js" ]
 }
 
+js_library("app_util.m") {
+  sources = [ "$root_gen_dir/ui/file_manager/base/js/app_util.m.js" ]
+  deps = [ "//ui/file_manager/externs:file_manager_private" ]
+  externs_list = [ "//ui/file_manager/externs/app_window_common.js" ]
+
+  extra_deps = [ ":modulize" ]
+}
+
 js_library("error_counter") {
 }
 
@@ -87,3 +102,7 @@ js_test_gen_html("js_test_gen_html") {
 
 js_library("mediasession_types") {
 }
+
+js_modulizer("modulize") {
+  input_files = [ "app_util.js" ]
+}

ui/file_manager/base/js/app_util.js

@@ -5,6 +5,7 @@
 /**
  * @fileoverview Utility functions for creating and operating on the packaged
  * AppWindow API.
+ * @suppress {uselessCode} Temporary suppress because of the line exporting.
  */
 
 const appUtil = {};
@@ -175,3 +176,6 @@ appUtil.AppCache.cleanup_ = map => {
     delete map[keys[i]];
   }
 };
+
+// eslint-disable-next-line semi,no-extra-semi
+/* #export */ {appUtil};