querySelectorAll should return List<Element>

sky/tests/framework/flights-app-pixels.sky

 <app>
   <import src="../resources/run-after-display.sky" />
   <style>
     * { box-sizing: border-box; }
 
     t, span {
       display: inline;
     }
 
     app {
@@ skipping 294 matching lines @@
   <script>
   import "dart:sky";
   import "dart:sky.internals" as internals;
   import "dart:async";
 
   var app;
 
   bool imagesLoaded() {
     var images = window.document.querySelectorAll('img');
     for (var i = 0; i < images.length; i++) {
-      if (!images.item(i).complete)
+      if (!images[i].complete)
         return false;
     }
     return true;
   }
 
   void checkImagesLoaded() {
     if (!imagesLoaded()) {
       new Timer(new Duration(seconds:10), checkImagesLoaded);
       return;
     }
     runAfterDisplay(() {
       internals.notifyTestComplete("");
     });
   }
   void main() {
     window.addEventListener("load", (_) {
       var input = document.querySelector('.input-text');
       window.getSelection().selectAllChildren(input.firstChild);
       checkImagesLoaded();
     });
   }
   </script>
 </app>