Generate Mojom Types in Dart (Take 2)

mojo/dart/embedder/embedder.gni

 # 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.
 
 # Template to generate a dart embedder package.
 # Required invoker inputs:
 #   String package (relative path to package e.g. mojo/public/interfaces/application)
 template("dart_embedder_package") {
   package = invoker.package
   package_path = "//$package"
 
   destination = package
   if (defined(invoker.destination)) {
     destination = invoker.destination
   }
 
   action_foreach(target_name) {
     deps = [
       package_path,
     ]
     list_generated_bindings_script =
         rebase_path(
             "//mojo/dart/embedder/tools/dart_list_generated_bindings.py")
     root_prefix = rebase_path("//")
     source_directory = rebase_path(package_path)
-    generated_bindings = exec_script(list_generated_bindings_script,
-                                     [
-                                       source_directory,
-                                       root_prefix,
-                                     ],
-                                     "list lines")
+
+    arguments = [
+      source_directory,
+      root_prefix,
+    ]
+    if (defined(invoker.is_bindings_types) && invoker.is_bindings_types) {
+      arguments += [ "--bindings-types" ]
+    }
+
+    generated_bindings =
+        exec_script(list_generated_bindings_script, arguments, "list lines")
     sources = rebase_path(generated_bindings, ".", root_gen_dir)
     outputs = [
       "$root_gen_dir/dart_embedder_packages/$destination/{{source_file_part}}",
     ]
     script = rebase_path(
             "//mojo/dart/embedder/tools/dart_rewrite_embedder_package_imports.py")
     args = [
       rebase_path("{{source}}", "", root_build_dir),
       rebase_path(
           "$root_gen_dir/dart_embedder_packages/$destination/{{source_file_part}}"),
@@ skipping 46 matching lines @@
     ]
     if (defined(invoker.input_directory)) {
       args += [
         "--client_root",
         rebase_path(invoker.input_directory),
       ]
     }
     args += rebase_path(invoker.inputs)
   }
 }