Fix names in named parameter lists

lib/src/codegen/js_codegen.dart

Index: lib/src/codegen/js_codegen.dart
diff --git a/lib/src/codegen/js_codegen.dart b/lib/src/codegen/js_codegen.dart
index 5e6df418f75c8463a730ee9826930511f8cda962..f8f50a54fcfa4652f7e44c5b9cc6968b7b156b75 100644
--- a/lib/src/codegen/js_codegen.dart
+++ b/lib/src/codegen/js_codegen.dart
@@ -1184,7 +1184,7 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
       {dynamicIsBottom: false}) {
     var properties = <JS.Property>[];
     types.forEach((name, type) {
-      var key = new JS.LiteralString(name);
+      var key = _propertyName(name);
       var value = _emitTypeName(type, dynamicIsBottom: dynamicIsBottom);
       properties.add(new JS.Property(key, value));
     });