Revert "Extensions: use preprocessing for generating rollup input"

This reverts commit a27166e7.

Reason for revert: Suspected many extension test failure: https://ci.chromium.org/p/chromium/builders/ci/Linux%20Tests%20%28dbg%29%281%29/91600

Original change's description:
> Extensions: use preprocessing for generating rollup input
> 
> Bug: 1128583
> Change-Id: If798fc3db54305ccbf2c795c0fae6c332ce34bbf
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2410352
> Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
> Reviewed-by: dpapad <dpapad@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#807199}

TBR=dpapad@chromium.org,rbpotter@chromium.org

Change-Id: I0ec45eec5cd962f42043eed80e0765f8e01e18c7
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1128583
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2409689Reviewed-by: Yoichi Osato <yoichio@chromium.org>
Commit-Queue: Yoichi Osato <yoichio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807291}

chrome/browser/resources/extensions/BUILD.gn

@@ -4,85 +4,51 @@
 
 import("//chrome/common/features.gni")
 import("//third_party/closure_compiler/compile_js.gni")
-import("//tools/grit/preprocess_grit.gni")
+import("//tools/grit/grit_rule.gni")
 import("//tools/polymer/html_to_js.gni")
 import("../optimize_webui.gni")
 
 if (optimize_webui) {
-  preprocess_folder = "preprocessed"
+  extensions_pak_file = "extensions_resources.pak"
+  unpak_folder = "extensions_resources.unpak"
 
   optimize_webui("build") {
     host = "extensions"
-    input = rebase_path("$target_gen_dir/$preprocess_folder", root_build_dir)
+    input = rebase_path("$target_gen_dir/$unpak_folder", root_build_dir)
     js_out_files = [ "extensions.rollup.js" ]
     js_module_in_files = [ "extensions.js" ]
 
     deps = [
-      ":preprocess",
-      ":preprocess_generated",
+      ":unpak",
       "../../../../ui/webui/resources:preprocess",
     ]
     excludes = [ "chrome://resources/js/cr.m.js" ]
   }
 
-  preprocess_grit("preprocess") {
-    in_folder = "./"
-    out_folder = "$target_gen_dir/$preprocess_folder"
-    in_files = [
-      "drag_and_drop_handler.js",
-      "extensions.js",
-      "item_behavior.js",
-      "item_util.js",
-      "keyboard_shortcut_delegate.js",
-      "navigation_helper.js",
-      "service.js",
-      "shortcut_util.js",
-    ]
+  unpak("unpak") {
+    pak_file = extensions_pak_file
+    out_folder = unpak_folder
 
-    if (is_chromeos) {
-      in_files += [ "kiosk_browser_proxy.js" ]
-    }
+    deps = [ ":flattened_resources" ]
   }
 
-  preprocess_grit("preprocess_generated") {
-    deps = [ ":web_components" ]
-    in_folder = target_gen_dir
-    out_folder = "$target_gen_dir/$preprocess_folder"
-    in_files = [
-      "checkup.js",
-      "code_section.js",
-      "activity_log/activity_log_history_item.js",
-      "activity_log/activity_log_history.js",
-      "activity_log/activity_log.js",
-      "activity_log/activity_log_stream_item.js",
-      "activity_log/activity_log_stream.js",
-      "detail_view.js",
-      "drop_overlay.js",
-      "error_page.js",
-      "host_permissions_toggle_list.js",
-      "icons.js",
-      "install_warnings_dialog.js",
-      "item.js",
-      "item_list.js",
-      "keyboard_shortcuts.js",
-      "load_error.js",
-      "manager.js",
-      "options_dialog.js",
-      "pack_dialog_alert.js",
-      "pack_dialog.js",
-      "runtime_host_permissions.js",
-      "runtime_hosts_dialog.js",
-      "shared_style.js",
-      "shared_vars.js",
-      "shortcut_input.js",
-      "sidebar.js",
-      "toggle_row.js",
-      "toolbar.js",
+  grit("flattened_resources") {
+    source = "extensions_resources.grd"
+
+    grit_flags = [
+      "-E",
+      "root_gen_dir=" + rebase_path(root_gen_dir, root_build_dir),
     ]
 
-    if (is_chromeos) {
-      in_files += [ "kiosk_dialog.js" ]
-    }
+    deps = [ ":web_components" ]
+    defines = chrome_grit_defines
+    outputs = [
+      "grit/extensions_resources.h",
+      "grit/extensions_resources_map.cc",
+      "grit/extensions_resources_map.h",
+      extensions_pak_file,
+    ]
+    output_dir = "$root_gen_dir/chrome/browser/resources/extensions"
   }
 }