Revert of 🍵 Refactor the various locale_paks() templates to be more shared

android_webview/webview_repack_locales.gni

Index: android_webview/webview_repack_locales.gni
diff --git a/android_webview/webview_repack_locales.gni b/android_webview/webview_repack_locales.gni
index c4655ee0d50ddcd976ea22642b21798ed3b0630b..cf121ac6fbdcdbd9daf1ec5bb3e90fa7b0418e12 100644
--- a/android_webview/webview_repack_locales.gni
+++ b/android_webview/webview_repack_locales.gni
@@ -1,32 +1,110 @@
 # Copyright 2015 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.
+#
+# This is a copy of src/chrome/chrome_repack_locales.gni with the necessary
+# modifications to meet WebView's requirement.
 
+import("//build/config/chrome_build.gni")
+import("//build/config/features.gni")
+import("//build/config/ui.gni")
 import("//tools/grit/repack.gni")
 import("webview_repack_locales_list.gni")
 
-# Wraps repack_locales(), setting the source_patterns and deps required for
-# Chrome.
-template("webview_repack_locales") {
-  repack_locales(target_name) {
-    forward_variables_from(invoker, "*")
+# Arguments:
+#
+#   locale
+#       Internal name of locale. e.g. "pt-BR"
+#
+#   output
+#       Output file name.
+#
+#   visibility
+#       Normal meaning.
+template("_repack_one_locale") {
+  locale = invoker.locale
+
+  repack(target_name) {
+    visibility = invoker.visibility
 
     # Adding webview specific pak file? You should add it to
     # webview_repack_locales_source_patterns, so it is also included in
     # Monochrome.
 
-    source_patterns = [
-      "${root_gen_dir}/android_webview/components_strings_",
-      "${root_gen_dir}/content/app/strings/content_strings_",
-      "${root_gen_dir}/ui/strings/app_locale_settings_",
+    # Each input pak file should also have a deps line for completeness.
+    sources = [
+      "${root_gen_dir}/android_webview/components_strings_${locale}.pak",
+      "${root_gen_dir}/content/app/strings/content_strings_${locale}.pak",
+      "${root_gen_dir}/ui/strings/app_locale_settings_${locale}.pak",
     ]
     deps = [
       "//android_webview:generate_components_strings",
       "//content/app/strings",
       "//ui/strings:app_locale_settings",
     ]
-    source_patterns += webview_repack_locales_source_patterns
+    sources += process_file_template(webview_repack_locales_source_patterns,
+                                     [ "{{source}}_${locale}.pak" ])
     deps += webview_repack_locales_deps
-    output_dir = "$root_out_dir/android_webview/locales"
+    output = invoker.output
   }
 }
+
+# Creates an action to call the repack_locales script.
+#
+# The GYP version generates the locales in the "gen" directory and then copies
+# it to the root build directory. This isn't easy to express in a GN copy
+# rule since the files on Mac have a complex structure. So we generate the
+# files into the final place and skip the "gen" directory.
+#
+# This template uses GN's looping constructs to avoid the complex call to
+# chrome/tools/build/repack_locales.py which wraps the repack commands in the
+# GYP build.
+#
+# Arguments
+#
+#   input_locales
+#       List of locale names to use as inputs.
+#
+#   output_locales
+#       A list containing the corresponding output names for each of the
+#       input names.
+#
+#   visibility
+template("webview_repack_locales") {
+  # This is the name of the group below that will collect all the invidual
+  # locale targets. External targets will depend on this.
+  group_target_name = target_name
+
+  # GN's subscript is too stupid to do invoker.output_locales[foo] so we need
+  # to make a copy and do output_locales[foo].
+  output_locales = invoker.output_locales
+
+  # Collects all targets the loop generates.
+  locale_targets = []
+
+  # This loop iterates over the input locales and also keeps a counter so it
+  # can simultaneously iterate over the output locales (using GN's very
+  # limited looping capabilities).
+  current_index = 0
+  foreach(input_locale, invoker.input_locales) {
+    output_locale = output_locales[current_index]
+
+    # Compute the name of the target for the current file. Save it for the deps.
+    current_name = "${target_name}_${input_locale}"
+    locale_targets += [ ":$current_name" ]
+
+    _repack_one_locale(current_name) {
+      visibility = [ ":$group_target_name" ]
+      locale = input_locale
+      output = "${root_out_dir}/android_webview/locales/${output_locale}.pak"
+    }
+
+    current_index = current_index + 1
+  }
+
+  # The group that external targets depend on which collects all deps.
+  group(group_target_name) {
+    forward_variables_from(invoker, [ "visibility" ])
+    public_deps = locale_targets
+  }
+}