Image loader: Run as JS modules

Background.m.js replaces background.js and background_scripts.js.
Update background.html to load the Image Loader as JS modules.
Optimize_webui to run Image Loader as JS modules.

Tests:
Load image loader and check that there is no additional error in
the console.
Current integration tests pass.

Bug: 1133186
Change-Id: I3cdf9fd2a59bca080b15c3efad51739a15fa93e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2635384
Commit-Queue: Jeremie Boulic <jboulic@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844703}

ui/file_manager/BUILD.gn

@@ -87,6 +87,7 @@ preprocess_if_expr("preprocess_static") {
     "file_manager/background/js/main_background.m.js",
     "file_manager/foreground/js/elements_importer.m.js",
     "file_manager/foreground/js/main.m.js",
+    "image_loader/background.m.js",
     "video_player/js/main.m.js",
     "video_player/js/main_background.m.js",
   ]
@@ -96,6 +97,7 @@ preprocess_if_expr("preprocess_static") {
     "//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/image_loader:background.m",
     "//ui/file_manager/video_player/js:main.m",
     "//ui/file_manager/video_player/js:main_background.m",
   ]
@@ -315,8 +317,14 @@ preprocess_if_expr("preprocess_generated") {
     "file_manager/cws_widget/cws_widget_container_platform_delegate.m.js",
 
     # Image Loader:
+    "image_loader/cache.m.js",
+    "image_loader/image_loader.m.js",
     "image_loader/image_loader_client.m.js",
+    "image_loader/image_loader_util.m.js",
+    "image_loader/image_request_task.m.js",
     "image_loader/load_image_request.m.js",
+    "image_loader/piex_loader.m.js",
+    "image_loader/scheduler.m.js",
 
     # Metadata:
     "file_manager/foreground/js/metadata/byte_reader.m.js",
@@ -383,6 +391,8 @@ generate_grd("build_grd") {
     "audio_player/js/main_background.m.rollup.js",
     "audio_player/js/metadata_worker.m.rollup.js",
 
+    "image_loader/background.m.rollup.js",
+
     "file_manager/background/js/main_background.m.rollup.js",
     "file_manager/foreground/elements/files_icon_button.m.js",
     "file_manager/foreground/elements/files_toggle_ripple.m.js",
@@ -396,6 +406,7 @@ generate_grd("build_grd") {
     "audio_player/js/main.m.rollup.js|audio_player/js/main.m.js",
     "audio_player/js/main_background.m.rollup.js|audio_player/js/main_background.m.js",
     "audio_player/js/metadata_worker.m.rollup.js|audio_player/js/metadata_worker.m.js",
+    "image_loader/background.m.rollup.js|image_loader/background.m.js",
     "file_manager/background/js/main_background.m.rollup.js|file_manager/background/js/main_background.m.js",
     "video_player/js/main.m.rollup.js|video_player/js/main.m.js",
     "video_player/js/main_background.m.rollup.js|video_player/js/main_background.m.js",
@@ -414,6 +425,7 @@ generate_grd("build_grd") {
     "//ui/file_manager/audio_player/js:build_worker",
     "//ui/file_manager/file_manager/background/js:build",
     "//ui/file_manager/file_manager/foreground/elements:elements",
+    "//ui/file_manager/image_loader:build",
     "//ui/file_manager/video_player/js:build",
     "//ui/file_manager/video_player/js:build_background",
   ]

ui/file_manager/file_manager_resources.grd

@@ -171,7 +171,6 @@
       <!-- Image loader extension manifest and scripts. -->
       <if expr="chromeos">
         <include name="IDR_IMAGE_LOADER_MANIFEST" file="image_loader/manifest.json" type="BINDATA" />
-        <include name="IDR_IMAGE_LOADER_BACKGROUND_JS" file="image_loader/background_scripts.js" flattenhtml="true" type="BINDATA" />
         <include name="IDR_IMAGE_LOADER_BACKGROUND_HTML" file="image_loader/background.html" type="BINDATA" />
         <include name="IDR_IMAGE_LOADER_CLIENT_JS" file="image_loader/image_loader_client.js" type="BINDATA" />
         <include name="IDR_IMAGE_LOADER_PIEX_WASM_JS" file="image_loader/piex/piex.js.wasm" type="BINDATA" />

ui/file_manager/image_loader/BUILD.gn

@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//chrome/browser/resources/tools/optimize_webui.gni")
 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")
@@ -10,6 +11,7 @@ import("//ui/webui/resources/tools/js_modulizer.gni")
 js_type_check("closure_compile_jsmodules") {
   uses_js_modules = true
   deps = [
+    ":background.m",
     ":cache.m",
     ":image_loader.m",
     ":image_loader_client.m",
@@ -24,7 +26,6 @@ js_type_check("closure_compile_jsmodules") {
 js_type_check("closure_compile_module") {
   closure_flags = default_closure_args + [ "jscomp_error=strictCheckTypes" ]
   deps = [
-    ":background",
     ":cache",
     ":image_loader",
     ":image_loader_client",
@@ -36,8 +37,8 @@ js_type_check("closure_compile_module") {
   ]
 }
 
-js_library("background") {
-  deps = [ ":image_loader" ]
+js_library("background.m") {
+  deps = [ ":image_loader.m" ]
 }
 
 js_library("cache") {
@@ -260,3 +261,22 @@ js_modulizer("modulize") {
     "image_loader.js",
   ]
 }
+
+preprocess_folder =
+    rebase_path("$target_gen_dir/../preprocessed/image_loader", root_build_dir)
+
+optimize_webui("build") {
+  host = "image_loader"
+
+  input = preprocess_folder
+  js_module_in_files = [ "background.m.js" ]
+
+  js_out_files = [ "background.m.rollup.js" ]
+
+  deps = [
+    ":background.m",
+    "//ui/file_manager:preprocess_generated",
+    "//ui/file_manager:preprocess_static",
+    "//ui/webui/resources:preprocess",
+  ]
+}

ui/file_manager/image_loader/background.html

 <!DOCTYPE html>
 <meta charset="utf-8">
 
-<script src="chrome://resources/js/assert.js"></script>
 <script src="piex/piex.js.wasm"></script>
-<script src="background_scripts.js"></script>
+<script type="module" src="background.m.js"></script>

ui/file_manager/image_loader/background.js → ui/file_manager/image_loader/background.m.js

-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright 2020 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 Entry point for Image Loader.
+ */
+
+import {ImageLoader} from './image_loader.m.js';
+
 // Load the extension.
 ImageLoader.getInstance();

ui/file_manager/image_loader/background_scripts.js

-// Copyright 2016 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.
-
-// <include src="../file_manager/common/js/file_type.js">
-// <include src="../file_manager/foreground/js/metadata/image_orientation.js">
-// <include src="cache.js">
-// <include src="load_image_request.js">
-// <include src="image_loader.js">
-// <include src="image_loader_util.js">
-// <include src="piex_loader.js">
-// <include src="image_request_task.js">
-// <include src="scheduler.js">
-// Entry point.
-// <include src="background.js">