Web UI: Change Print Preview to use preprocess instead of pak/unpak

Proof of concept CL updating Print Preview to use the new
grit_preprocess build rule to generate inputs for rollup, instead of
generating a pak file and unpak folder from the grd file.

Bug: 1071641
Change-Id: Ic9a15c6c546be979ce68ad4d90537c142163a024
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2370162Reviewed-by: dpapad <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#802281}

chrome/browser/resources/print_preview/BUILD.gn

@@ -4,22 +4,21 @@
 
 import("//chrome/common/features.gni")
 import("//third_party/closure_compiler/compile_js.gni")
-import("//tools/grit/grit_rule.gni")
-import("//tools/polymer/polymer.gni")
+import("//tools/grit/preprocess_grit.gni")
 import("../optimize_webui.gni")
 
 if (optimize_webui) {
-  print_preview_pak_file = "print_preview_resources.pak"
-  unpak_folder = "print_preview_resources.unpak"
+  preprocess_folder = "print_preview_preprocessed"
 
   optimize_webui("build") {
     host = "print"
-    input = rebase_path("$target_gen_dir/$unpak_folder", root_build_dir)
+    input = rebase_path("$target_gen_dir/$preprocess_folder", root_build_dir)
     js_out_files = [ "print_preview.rollup.js" ]
     js_module_in_files = [ "print_preview.js" ]
 
     deps = [
-      ":unpak",
+      ":preprocess",
+      ":preprocess_generated",
       "../../../../ui/webui/resources:modulize",
     ]
     excludes = [
@@ -28,33 +27,103 @@ if (optimize_webui) {
     ]
   }
 
-  unpak("unpak") {
-    pak_file = print_preview_pak_file
-    out_folder = unpak_folder
+  preprocess_grit("preprocess") {
+    in_folder = "./"
+    out_folder = "$target_gen_dir/$preprocess_folder"
+    in_files = [
+      "cloud_print_interface.js",
+      "cloud_print_interface_impl.js",
+      "dark_mode_behavior.js",
+      "metrics.js",
+      "native_layer.js",
+      "print_preview.js",
+      "print_preview_utils.js",
+      "data/cloud_parsers.js",
+      "data/coordinate2d.js",
+      "data/destination.js",
+      "data/destination_match.js",
+      "data/destination_policies.js",
+      "data/destination_store.js",
+      "data/document_info.js",
+      "data/invitation.js",
+      "data/invitation_store.js",
+      "data/local_parsers.js",
+      "data/margins.js",
+      "data/measurement_system.js",
+      "data/model.js",
+      "data/printable_area.js",
+      "data/scaling.js",
+      "data/size.js",
+      "data/state.js",
+      "data/user_manager.js",
+      "ui/highlight_utils.js",
+      "ui/input_behavior.js",
+      "ui/plugin_proxy.js",
+      "ui/select_behavior.js",
+      "ui/settings_behavior.js",
+    ]
 
-    deps = [ ":flattened_resources" ]
+    if (is_chromeos) {
+      in_files += [ "data/printer_status_cros.js" ]
+    }
   }
 
-  grit("flattened_resources") {
-    source = "print_preview_resources.grd"
-
-    grit_flags = [
-      "-E",
-      "root_gen_dir=" + rebase_path(root_gen_dir, root_build_dir),
+  preprocess_grit("preprocess_generated") {
+    deps = [ "ui:web_components" ]
+    in_folder = target_gen_dir
+    out_folder = "$target_gen_dir/$preprocess_folder"
+    in_files = [
+      "ui/advanced_options_settings.js",
+      "ui/advanced_settings_dialog.js",
+      "ui/advanced_settings_item.js",
+      "ui/app.js",
+      "ui/button_strip.js",
+      "ui/color_settings.js",
+      "ui/copies_settings.js",
+      "ui/destination_dialog.js",
+      "ui/destination_list.js",
+      "ui/destination_list_item.js",
+      "ui/destination_select_css.js",
+      "ui/destination_settings.js",
+      "ui/dpi_settings.js",
+      "ui/duplex_settings.js",
+      "ui/header.js",
+      "ui/icons.js",
+      "ui/layout_settings.js",
+      "ui/margin_control.js",
+      "ui/margin_control_container.js",
+      "ui/margins_settings.js",
+      "ui/media_size_settings.js",
+      "ui/more_settings.js",
+      "ui/number_settings_section.js",
+      "ui/other_options_settings.js",
+      "ui/pages_per_sheet_settings.js",
+      "ui/pages_settings.js",
+      "ui/preview_area.js",
+      "ui/print_preview_search_box.js",
+      "ui/print_preview_shared_css.js",
+      "ui/print_preview_vars_css.js",
+      "ui/provisional_destination_resolver.js",
+      "ui/scaling_settings.js",
+      "ui/settings_section.js",
+      "ui/settings_select.js",
+      "ui/sidebar.js",
+      "ui/throbber_css.js",
     ]
 
-    deps = [
-      "../pdf:web_components",
-      "ui:web_components",
-    ]
-    defines = chrome_grit_defines
-    outputs = [
-      "grit/print_preview_resources.h",
-      "grit/print_preview_resources_map.cc",
-      "grit/print_preview_resources_map.h",
-      print_preview_pak_file,
-    ]
-    output_dir = "$root_gen_dir/chrome/browser/resources/print_preview"
+    if (is_chromeos) {
+      in_files += [
+        "ui/destination_dropdown_cros.js",
+        "ui/destination_select_cros.js",
+        "ui/pin_settings.js",
+        "ui/printer_status_icon_cros.js",
+      ]
+    } else {
+      in_files += [
+        "ui/destination_select.js",
+        "ui/link_container.js",
+      ]
+    }
   }
 }