Files app: Add main.m.js

This is a preparation to run Files app as JS modules.

Bug: 1133186
Change-Id: I0447d7c19950c69aa47ecb33f5df35a0fcb330d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2636814
Commit-Queue: Jeremie Boulic <jboulic@chromium.org>
Auto-Submit: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: Jeremie Boulic <jboulic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844679}

ui/file_manager/BUILD.gn

@@ -86,6 +86,7 @@ preprocess_if_expr("preprocess_static") {
     "audio_player/js/main_background.m.js",
     "file_manager/background/js/main_background.m.js",
     "file_manager/foreground/js/elements_importer.m.js",
+    "file_manager/foreground/js/main.m.js",
     "video_player/js/main.m.js",
     "video_player/js/main_background.m.js",
   ]
@@ -94,6 +95,7 @@ preprocess_if_expr("preprocess_static") {
     "//ui/file_manager/audio_player/js:main.m",
     "//ui/file_manager/audio_player/js:main_background.m",
     "//ui/file_manager/file_manager/background/js:main_background.m",
+    "//ui/file_manager/file_manager/foreground/js:main.m",
     "//ui/file_manager/video_player/js:main.m",
     "//ui/file_manager/video_player/js:main_background.m",
   ]

ui/file_manager/file_manager/foreground/js/BUILD.gn

@@ -62,6 +62,7 @@ js_type_check("closure_compile_jsmodules") {
     ":last_modified_controller.m",
     ":launch_param.m",
     ":list_thumbnail_loader.m",
+    ":main.m",
     ":main_window_component.m",
     ":metadata_box_controller.m",
     ":metadata_update_controller.m",
@@ -1442,6 +1443,15 @@ js_library("main") {
   ]
 }
 
+js_library("main.m") {
+  visibility += [ "//ui/file_manager:*" ]
+  deps = [
+    ":file_manager.m",
+    ":metrics_start.m",
+    "//ui/file_manager/file_manager/common/js:util.m",
+  ]
+}
+
 js_library("main_window_component") {
   deps = [
     ":app_state_controller",

ui/file_manager/file_manager/foreground/js/main.m.js

+// Copyright 2021 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.
+
+/**
+ * @fileoverview Start point for Files app.
+ */
+
+import '../../../base/js/error_counter.m.js';
+import './metrics_start.m.js';
+
+import {util} from '../../common/js/util.m.js';
+import {FileManager} from './file_manager.m.js';
+
+
+const fileManager = new FileManager();
+window.fileManager = fileManager;
+
+fileManager.initializeCore();
+
+fileManager.initializeUI(document.body)
+    .then(() => util.testSendMessage('ready'));