Add all dart:html tests from the sdk to test/codegen.

test/codegen/lib/html/wheelevent_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library wheel_event_test;
+
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+import 'dart:html';
+
+main() {
+  useHtmlConfiguration();
+
+  test('wheelEvent', () {
+    var element = new DivElement();
+    var eventType = Element.mouseWheelEvent.getEventType(element);
+
+    element.onMouseWheel.listen(expectAsync((e) {
+      expect(e.screen.x, 100);
+      expect(e.deltaX, 0);
+      expect(e.deltaY.toDouble(), 240.0);
+      expect(e.deltaMode, WheelEvent.DOM_DELTA_PAGE);
+    }));
+    var event = new WheelEvent(eventType,
+        deltaX: 0,
+        deltaY: 240,
+        deltaMode: WheelEvent.DOM_DELTA_PAGE,
+        screenX: 100);
+    element.dispatchEvent(event);
+  });
+
+  test('wheelEvent with deltaZ', () {
+    var element = new DivElement();
+    var eventType = Element.mouseWheelEvent.getEventType(element);
+
+    element.onMouseWheel.listen(expectAsync((e) {
+      expect(e.deltaX, 0);
+      expect(e.deltaY, 0);
+      expect(e.screen.x, 0);
+      expect(e.deltaZ.toDouble(), 1.0);
+    }));
+    var event = new WheelEvent(eventType, deltaZ: 1.0);
+    element.dispatchEvent(event);
+  });
+
+  test('wheelEvent Stream', () {
+    var element = new DivElement();
+    var eventType = Element.mouseWheelEvent.getEventType(element);
+
+    element.onMouseWheel.listen(expectAsync((e) {
+      expect(e.screen.x, 100);
+      expect(e.deltaX.toDouble(), 240.0);
+      expect(e.deltaY, 0);
+    }));
+    var event = new WheelEvent(eventType, deltaX: 240, deltaY: 0, screenX: 100);
+    element.dispatchEvent(event);
+  });
+}