bind-gen: Support stopping the old bindings generation of IDL callback

Supports stopping the old bindings generation of IDL callback
functions so that we can enable the new bindings generator.

Bug: 839389
Change-Id: Ic84f8b6630d2f77983e551083a93c2de3423f954
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2434184Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811161}

third_party/blink/renderer/bindings/scripts/idl_compiler.py

@@ -52,6 +52,9 @@ def parse_options():
         '--cache-directory',
         help='cache directory, defaults to output directory')
     parser.add_option('--generate-impl', action='store_true', default=False)
+    parser.add_option('--generate-impl-skip-callback-function',
+                      action='store_true',
+                      default=False)
     parser.add_option(
         '--read-idl-list-from-file', action='store_true', default=False)
     parser.add_option('--output-directory')
@@ -190,6 +193,7 @@ def main():
                                  options, input_filenames)
         generate_union_type_containers(CodeGeneratorUnionType, info_provider,
                                        options)
+        if not options.generate_impl_skip_callback_function:
             generate_callback_function_impl(CodeGeneratorCallbackFunction,
                                             info_provider, options)
     else:

third_party/blink/renderer/bindings/scripts/scripts.gni

@@ -287,8 +287,11 @@ template("idl_impl") {
       "--target-component",
       invoker.target_component,
       "--generate-impl",
-      rebase_path(idl_files_list, root_build_dir),
     ]
+    if (use_blink_v8_binding_new_idl_callback_function) {
+      args += [ "--generate-impl-skip-callback-function" ]
+    }
+    args += [ rebase_path(idl_files_list, root_build_dir) ]
 
     deps = [
       "//third_party/blink/renderer/bindings:interfaces_info",