web file transfer (#9587)

Signed-off-by: 21pages <sunboeasy@gmail.com>

flutter/lib/web/web_unique.dart

@@ -0,0 +1,30 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:js' as js;
+
+Future<void> webselectFiles({required bool is_folder}) async {
+  return Future(
+      () => js.context.callMethod('setByName', ['select_files', is_folder]));
+}
+
+Future<void> webSendLocalFiles(
+    {required int handleIndex,
+    required int actId,
+    required String path,
+    required String to,
+    required int fileNum,
+    required bool includeHidden,
+    required bool isRemote}) {
+  return Future(() => js.context.callMethod('setByName', [
+        'send_local_files',
+        jsonEncode({
+          'id': actId,
+          'handle_index': handleIndex,
+          'path': path,
+          'to': to,
+          'file_num': fileNum,
+          'include_hidden': includeHidden,
+          'is_remote': isRemote,
+        })
+      ]));
+}