update elements and fix some bugs

test/iron_icon_test.dart

Index: test/iron_icon_test.dart
diff --git a/test/iron_icon_test.dart b/test/iron_icon_test.dart
index 087cfc191a65e5db5386235a18927651cad732ca..4d585fdaff7b77bfe20fdc2e8a74b8398b51cbfe 100644
--- a/test/iron_icon_test.dart
+++ b/test/iron_icon_test.dart
@@ -69,11 +69,27 @@ main() async {
             style.backgroundPosition, contains(new RegExp(r'-24px 0(%|px)')));
       });
     });
+
     group('when no icon source is provided', () {
       test('will politely wait for an icon source without throwing', () {
         document.createElement('iron-icon');
         fixture('WithoutAnIconSource');
       });
     });
+
+    group('when loading async', () {
+      test('will get icon after iconset is added', () {
+        var icon = fixture('UsingAsyncIconset');
+        expect(hasIcon(icon), isFalse);
+
+        var done = window.on['iron-iconset-added'].first.then((_) {
+          expect(hasIcon(icon), isTrue,
+              reason: 'icon didn\'t load after iconset loaded');
+        });
+        fixture('AsyncIconset');
+
+        return done;
+      });
+    });
   });
 }