anchor.diff:  
     Future load() {
       _webviewReady = new Completer();
  -    
  -     // TODO(ussuri): BUG #3466.
  +
  +    // TODO(ussuri): BUG #3466.
       new Timer(new Duration(milliseconds: 500), () {
         _webviewElt = new Element.tag('webview');
   
  
positive.code:     // TODO(ussuri): Check the sender?
      return _injectScriptIntoWebviewMainWorld(r'''
          window.addEventListener("message", function(event) {
            var designer = document.querySelector("#designer");
            var action = event.data['action'];
            if (action === 'export_code') {
              chrome.runtime.sendMessage(
  
negative.code:   }
  
    Future _injectScriptIntoWebviewMainWorld(String script) {
      script = script.replaceAll('"', r'\"')
                     .replaceAll("'", r"\'")
                     .replaceAll('\n', r'\n');
      return _executeScriptInWebview(r'''
          (function() {
            var scriptTag = document.createElement('script');
            scriptTag.innerHTML = '(function() { ''' + script + r'''; })()';
            document.body.appendChild(scriptTag);
          })();
      ''');
    }
  