Combine window.setTimeout/setInterval with Timer and Timer.repeating. Also

samples/isolate_html/isolate_sample.dart

Index: samples/isolate_html/isolate_sample.dart
diff --git a/samples/isolate_html/isolate_sample.dart b/samples/isolate_html/isolate_sample.dart
index f3a9079ecf11a2dc44f7a8baa21bd35d42d19f8a..4f239a8811329435a40c7afd7fbf8ffdb846e733 100644
--- a/samples/isolate_html/isolate_sample.dart
+++ b/samples/isolate_html/isolate_sample.dart
@@ -75,11 +75,9 @@ void isolateMain() {
     if (div.query('input.replyCheckbox').checked) {
       InputElement element = div.query('.delayTextbox');
       int millis = int.parse(element.value);
-      // TODO(justinfagnani): use Timer when it works in isolates in dart2js
-      // see: http://dartbug.com/4997
-      window.setTimeout(() {
+      new Timer(new Duration(milliseconds: millis), () {
         replyTo.send('this is a reply from isolate "${isolateName}"', null);
-      }, millis);
+      });
     }
   }