Add constructors to all the event classes.

client/touch/Scroller.dart

 // Copyright (c) 2011, 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.
 
 /**
  * Implementation of a custom scrolling behavior.
  * This behavior overrides native scrolling for an area. This area can be a
  * single defined part of a page, the entire page, or several different parts
  * of a page.
  *
@@ skipping 302 matching lines @@
     if (snappedTarget != currentTarget) {
       _momentum.abort();
       reconfigure();
 
       _startDeceleration(
           _momentum.calculateVelocity(
               _contentOffset,
               snappedTarget,
               decelerationFactor),
           decelerationFactor);
-      onDecelStart.dispatch(
-          EventUtil.createEvent(ScrollerEventType.DECEL_START));
+      onDecelStart.dispatch(new Event(ScrollerEventType.DECEL_START));
       return true;
     } else {
       return false;
     }
   }
 
   bool throwDelta(num deltaX, num deltaY, [num decelerationFactor = null]) {
     Coordinate start = _contentOffset;
     Coordinate end = currentTarget;
     int x = end.x.toInt();
@@ skipping 88 matching lines @@
                     String timingFunction = null]) {
     // TODO(jacobr): remove once dartc fixes default args.
     if (duration === null) {
       duration = 0;
     }
     animateTo(x, y, duration, timingFunction);
   }
 
   void onDecelerationEnd() {
     _setWebkitTransition(_element, 0);
-    onScrollerEnd.dispatch(
-        EventUtil.createEvent(ScrollerEventType.SCROLLER_END));
+    onScrollerEnd.dispatch(new Event(ScrollerEventType.SCROLLER_END));
     _started = false;
   }
 
   void onDragEnd() {
     _dragInProgress = false;
 
     bool decelerating = false;
     if (_activeGesture) {
       if (_momentumEnabled && !_activeTransition) {
         decelerating = _startDeceleration(_touchHandler.getEndVelocity());
       }
     }
 
-    onScrollerDragEnd.dispatch(
-        EventUtil.createEvent(ScrollerEventType.DRAG_END));
+    onScrollerDragEnd.dispatch(new Event(ScrollerEventType.DRAG_END));
 
     if (!decelerating) {
       _snapContentOffsetToBounds();
-      onScrollerEnd.dispatch(
-          EventUtil.createEvent(ScrollerEventType.SCROLLER_END));
+      onScrollerEnd.dispatch(new Event(ScrollerEventType.SCROLLER_END));
       _started = false;
     } else {
-      onDecelStart.dispatch(
-          EventUtil.createEvent(ScrollerEventType.DECEL_START));
+      onDecelStart.dispatch(new Event(ScrollerEventType.DECEL_START));
     }
     _activeGesture = false;
   }
 
   void onDragMove() {
     if (_isStopping || (!_activeGesture && _dragInProgress)) {
       return;
     }
 
     assert(_contentStartOffset != null); // Content start not set
     Coordinate contentStart = _contentStartOffset;
     num newX = contentStart.x + _touchHandler.getDragDeltaX();
     num newY = contentStart.y + _touchHandler.getDragDeltaY();
     newY = _shouldScrollVertically() ?
         _adjustValue(newY, _minPoint.y, _maxPoint.y) : 0;
     newX = _shouldScrollHorizontally() ?
         _adjustValue(newX, _minPoint.x, _maxPoint.x) : 0;
     if (!_activeGesture) {
       _activeGesture = true;
       _dragInProgress = true;
     }
     if (!_started) {
       _started = true;
-      onScrollerStart.dispatch(
-          EventUtil.createEvent(ScrollerEventType.SCROLLER_START));
+      onScrollerStart.dispatch(new Event(ScrollerEventType.SCROLLER_START));
     }
     _setContentOffset(newX, newY);
   }
 
   bool onDragStart(TouchEvent e) {
     if (e.touches.length > 1) {
       return false;
     }
     bool shouldHorizontal = _shouldScrollHorizontally();
     bool shouldVertical = _shouldScrollVertically();
@@ skipping 78 matching lines @@
     return new Coordinate(clampX, clampY);
   }
 
   /**
    * Translate the content to a new position specified in px.
    */
   void _setContentOffset(num x, num y) {
     _contentOffset.x = x;
     _contentOffset.y = y;
     _setOffsetFunction(_element, x, y);
-    onContentMoved.dispatch(
-        EventUtil.createEvent(ScrollerEventType.CONTENT_MOVED));
+    onContentMoved.dispatch(new Event(ScrollerEventType.CONTENT_MOVED));
   }
 
   /**
    * Sets the offset to subtract from the maximum coordinate that the left upper
    * corner of the content can scroll to.
    */
   void setMaxOffset(num x, num y) {
     _maxOffset.x = x;
     _maxOffset.y = y;
     _resize();
@@ skipping 202 matching lines @@
     for (EventListener listener in _listeners) {
       listener(evt);
     }
   }
 }
 
 class ScrollerScrollTechnique {
   static final TRANSFORM_3D = 1;
   static final RELATIVE_POSITIONING = 2;
 }