anchor.diff:  Never TODO([String message = '']) => throw UnimplementedError(message);
   ''';
   
  -  String _decorateJavaScript(String javaScript, {String modulesBaseUrl}) {
  -    final postMessagePrint = '''
  +  String _decorateJavaScript(String javaScript,
  +      {@required String modulesBaseUrl}) {
  +    final completeScript = StringBuffer();
  +    // postMessagePrint:
  +    completeScript.writeln('''
   var testKey = '$testKey';
   
   function dartPrint(message) {
  
positive.code: 
  import 'dart:async';
  import 'dart:html';
  
  import 'execution.dart';
  
  
negative.code:   void replaceCss(String css) {
      _send('setCss', {'css': css});
    }
  
    @override
    Future tearDown() => _reset();
  
    set frameSrc(String src) {
      frame.src = src;
  