Implement JS_INTERCEPTOR_CONSTANT

sdk/lib/_internal/lib/interceptors.dart

Index: sdk/lib/_internal/lib/interceptors.dart
diff --git a/sdk/lib/_internal/lib/interceptors.dart b/sdk/lib/_internal/lib/interceptors.dart
index e87ce4fad2b33c5a7b074ba2edba124c2e4874fb..f56d4243d99c511f26cd9334526a8ab0afc71896 100644
--- a/sdk/lib/_internal/lib/interceptors.dart
+++ b/sdk/lib/_internal/lib/interceptors.dart
@@ -27,7 +27,7 @@ import 'dart:_js_helper' show allMatchesInStringUnchecked,
                               lookupDispatchRecord,
                               StringMatch,
                               firstMatchAfter;
-import 'dart:_foreign_helper' show JS, JS_EFFECT;
+import 'dart:_foreign_helper' show JS, JS_EFFECT, JS_INTERCEPTOR_CONSTANT;
 import 'dart:math' show Random;
 
 part 'js_array.dart';
@@ -145,7 +145,7 @@ getNativeInterceptor(object) {
 
   record = lookupDispatchRecord(object);
   if (record == null) {
-    return const UnknownJavaScriptObject();
+    return JS_INTERCEPTOR_CONSTANT(UnknownJavaScriptObject);
   }
   setDispatchProperty(JS('', 'Object.getPrototypeOf(#)', object), record);
   return getNativeInterceptor(object);