Downloads: Use preprocessing to generate rollup input

Note: This CL also demonstrates using a 3rd preprocess_grit target to
preprocess and copy the downloads mojo file to the desired relative
location in the preprocessed folder. This allows it to be included in
the bundle generated by rollup.

Bug: 1128583
Change-Id: I5a6e9825ba82110f1df4b5193dc21a8ef6178d78
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2414564
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: dpapad <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808223}

chrome/browser/resources/downloads/BUILD.gn

@@ -4,58 +4,62 @@
 
 import("//chrome/common/features.gni")
 import("//third_party/closure_compiler/compile_js.gni")
-import("//tools/grit/grit_rule.gni")
+import("//tools/grit/preprocess_grit.gni")
 import("//tools/polymer/html_to_js.gni")
 import("../optimize_webui.gni")
 
 if (optimize_webui) {
-  downloads_pak_file = "downloads_resources.pak"
-  unpak_folder = "downloads_resources.unpak"
+  preprocess_folder = "preprocess"
 
   optimize_webui("build") {
     host = "downloads"
-    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 = [ "downloads.rollup.js" ]
     js_module_in_files = [ "downloads.js" ]
     excludes = [
       "chrome://resources/js/cr.m.js",
       "chrome://resources/mojo/mojo/public/js/mojo_bindings_lite.js",
-      "downloads.mojom-lite.js",
     ]
 
     deps = [
-      ":unpak",
+      ":preprocess",
+      ":preprocess_generated",
+      ":preprocess_mojo",
       "../../../../ui/webui/resources:preprocess",
     ]
   }
 
-  unpak("unpak") {
-    pak_file = downloads_pak_file
-    out_folder = unpak_folder
-    excludes = [ "../../ui/webui/downloads/downloads.mojom-lite.js" ]
-
-    deps = [ ":flattened_resources" ]
+  preprocess_grit("preprocess") {
+    in_folder = "./"
+    out_folder = "$target_gen_dir/$preprocess_folder"
+    in_files = [
+      "browser_proxy.js",
+      "constants.js",
+      "downloads.js",
+      "externs.js",
+      "icon_loader.js",
+      "search_service.js",
+    ]
   }
 
-  grit("flattened_resources") {
-    source = "downloads_resources.grd"
-
-    defines = chrome_grit_defines
-    outputs = [
-      "grit/downloads_resources.h",
-      "grit/downloads_resources_map.cc",
-      "grit/downloads_resources_map.h",
-      downloads_pak_file,
+  preprocess_grit("preprocess_generated") {
+    deps = [ ":web_components" ]
+    in_folder = target_gen_dir
+    out_folder = "$target_gen_dir/$preprocess_folder"
+    in_files = [
+      "icons.js",
+      "item.js",
+      "manager.js",
+      "toolbar.js",
     ]
-    deps = [
-      ":web_components",
-      "//chrome/browser/ui/webui/downloads:mojo_bindings_js",
-    ]
-    grit_flags = [
-      "-E",
-      "root_gen_dir=" + rebase_path(root_gen_dir, root_build_dir),
+  }
+
+  copy("preprocess_mojo") {
+    deps = [ "//chrome/browser/ui/webui/downloads:mojo_bindings_js" ]
+    sources = [
+      "$root_gen_dir/chrome/browser/ui/webui/downloads/downloads.mojom-lite.js",
     ]
-    output_dir = "$root_gen_dir/chrome/browser/resources/downloads"
+    outputs = [ "$target_gen_dir/$preprocess_folder/downloads.mojom-lite.js" ]
   }
 }
 

chrome/browser/resources/downloads/downloads_resources.grd

@@ -14,64 +14,51 @@
     <includes>
       <include name="IDR_DOWNLOADS_IMAGES_INCOGNITO_MARKER_SVG"
           file="images\incognito_marker.svg"
-          compress="false"
           type="BINDATA" />
       <include name="IDR_DOWNLOADS_IMAGES_NO_DOWNLOADS_SVG"
           file="images\no_downloads.svg"
-          compress="false"
           type="BINDATA" />
       <include name="IDR_DOWNLOADS_MOJO_LITE_JS"
           file="${root_gen_dir}\chrome\browser\ui\webui\downloads\downloads.mojom-lite.js"
           use_base_dir="false"
-          compress="false"
           type="chrome_html" />
       <include name="IDR_DOWNLOADS_MANAGER_JS"
           file="${root_gen_dir}\chrome\browser\resources\downloads\manager.js"
           use_base_dir="false"
           preprocess="true"
-          compress="false"
           type="chrome_html" />
       <include name="IDR_DOWNLOADS_ITEM_JS"
           file="${root_gen_dir}\chrome\browser\resources\downloads\item.js"
           use_base_dir="false"
-          compress="false"
           type="chrome_html" />
       <include name="IDR_DOWNLOADS_TOOLBAR_JS"
           file="${root_gen_dir}\chrome\browser\resources\downloads\toolbar.js"
           use_base_dir="false"
-          compress="false"
           type="chrome_html" />
       <include name="IDR_DOWNLOADS_ICONS_JS"
           file="${root_gen_dir}\chrome\browser\resources\downloads\icons.js"
           use_base_dir="false"
-          compress="false"
           type="chrome_html" />
     </includes>
     <structures>
       <structure name="IDR_DOWNLOADS_DOWNLOADS_HTML"
           file="downloads.html"
           preprocess="true"
-          compress="false"
           type="chrome_html" />
       <structure name="IDR_DOWNLOADS_BROWSER_PROXY_JS"
           file="browser_proxy.js"
-          compress="false"
           type="chrome_html" />
       <structure name="IDR_DOWNLOADS_CONSTANTS_JS"
           file="constants.js"
-          compress="false"
           type="chrome_html" />
       <structure name="IDR_DOWNLOADS_DOWNLOADS_JS"
           file="downloads.js"
-          compress="false"
           type="chrome_html" />
       <structure name="IDR_DOWNLOADS_ICON_LOADER_JS"
           file="icon_loader.js"
-          compress="false"
           type="chrome_html" />
       <structure name="IDR_DOWNLOADS_SEARCH_SERVICE_JS"
           file="search_service.js"
-          compress="false"
           type="chrome_html" />
     </structures>
   </release>

chrome/browser/resources/downloads/downloads_resources_vulcanized.grd

@@ -18,10 +18,6 @@
       <include name="IDR_DOWNLOADS_IMAGES_NO_DOWNLOADS_SVG"
                file="images\no_downloads.svg"
                type="BINDATA" />
-      <include name="IDR_DOWNLOADS_MOJO_LITE_JS"
-               file="${root_gen_dir}\chrome\browser\ui\webui\downloads\downloads.mojom-lite.js"
-               use_base_dir="false"
-               type="BINDATA" />
       <include name="IDR_DOWNLOADS_DOWNLOADS_HTML"
                file="downloads.html"
                preprocess="true"

chrome/browser/ui/webui/downloads/downloads_ui.cc

@@ -167,8 +167,10 @@ content::WebUIDataSource* CreateDownloadsUIHTMLSource(Profile* profile) {
                           IDR_DOWNLOADS_IMAGES_INCOGNITO_MARKER_SVG);
   source->AddResourcePath("images/no_downloads.svg",
                           IDR_DOWNLOADS_IMAGES_NO_DOWNLOADS_SVG);
+#if !BUILDFLAG(OPTIMIZE_WEBUI)
   source->AddResourcePath("downloads.mojom-lite.js",
                           IDR_DOWNLOADS_MOJO_LITE_JS);
+#endif
 
   source->AddBoolean(
       "allowOpenNow",