bind-gen: Port a temporary support of @@asyncIterator to the new impl

Ports a temporary support of @@asyncIterator introduced at
https://crrev.com/c/2248414 to the new IDL interface
implementation.

Bug: 839389
Change-Id: Ib0ea64ec8c8fbc582ba5472ab8d10ee4b43e0e07
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2312456Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791719}

third_party/blink/renderer/bindings/scripts/bind_gen/interface.py

@@ -4967,6 +4967,22 @@ ${prototype_object}->Delete(
             nodes.append(
                 TextNode(_format(pattern, property_name=property_name)))
 
+    if class_like.identifier == "FileSystemDirectoryHandle":
+        pattern = """\
+// Temporary @@asyncIterator support for FileSystemDirectoryHandle
+// TODO(https://crbug.com/1087157): Replace with proper bindings support.
+// @@asyncIterator == "{property_name}"
+{{
+  v8::Local<v8::Value> v8_value = ${prototype_object}->Get(
+      ${v8_context}, V8AtomicString(${isolate}, "{property_name}"))
+      .ToLocalChecked();
+  ${prototype_object}->DefineOwnProperty(
+      ${v8_context}, v8::Symbol::GetAsyncIterator(${isolate}), v8_value,
+      v8::DontEnum).ToChecked();
+}}
+"""
+        nodes.append(TextNode(_format(pattern, property_name="entries")))
+
     if ("Global" in class_like.extended_attributes
             and class_like.indexed_and_named_properties
             and class_like.indexed_and_named_properties.has_named_properties):
@@ -5101,6 +5117,23 @@ def make_install_interface_template(cg_context, function_name, class_name,
       V8AtomicString(${isolate}, "prototype"), v8::kErrorPrototype);
   ${interface_template}->Inherit(intrinsic_error_prototype_interface_template);
 }
+"""))
+
+    if class_like.identifier == "NativeFileSystemDirectoryIterator":
+        body.append(
+            T("""\
+// Temporary @@asyncIterator support for FileSystemDirectoryHandle
+// TODO(https://crbug.com/1087157): Replace with proper bindings support.
+{
+  v8::Local<v8::FunctionTemplate>
+      intrinsic_iterator_prototype_interface_template =
+      v8::FunctionTemplate::New(${isolate});
+  intrinsic_iterator_prototype_interface_template->RemovePrototype();
+  intrinsic_iterator_prototype_interface_template->SetIntrinsicDataProperty(
+      V8AtomicString(${isolate}, "prototype"), v8::kAsyncIteratorPrototype);
+  ${interface_template}->Inherit(
+      intrinsic_iterator_prototype_interface_template);
+}
 """))
 
     if class_like.identifier == "HTMLAllCollection":