Adding scroll sequence and scroll support for the Navigation control.

src/ol/event/Drag.js

@@ -8,6 +8,10 @@ goog.require('goog.fx.Dragger.EventType');
 
 
 /**
+ * Event sequence that provides a 'dragstart', 'drag' and 'dragend' events.
+ * Event objects of the 'drag' events have 'deltaX' and 'deltaY' values with
+ * the relative pixel movement since the previous 'drag' or 'dragstart' event.
+ *
  * @constructor
  * @param {ol.event.Events} target The Events instance that handles events.
  * @implements {ol.event.ISequence}
@@ -34,8 +38,8 @@ ol.event.Drag = function(target) {
     });
     dragger.addEventListener(goog.fx.Dragger.EventType.DRAG, function(evt) {
         evt.target = element;
-        evt.dx = evt.clientX - previousX;
-        evt.dy = evt.clientY - previousY;
+        evt.deltaX = evt.clientX - previousX;
+        evt.deltaY = evt.clientY - previousY;
         previousX = evt.clientX;
         previousY = evt.clientY;
         target.triggerEvent(evt.type, evt);

src/ol/event/Scroll.js

@@ -0,0 +1,43 @@
+goog.provide('ol.event.Scroll');
+
+goog.require('ol.event.ISequence');
+goog.require('ol.event');
+goog.require('goog.events.MouseWheelHandler');
+
+
+/**
+ * Event sequence that provides a 'scroll' event. Event objects have 'deltaX'
+ * and 'deltaY' values with the scroll delta since the previous 'scroll' event.
+ *
+ * @constructor
+ * @param {ol.event.Events} target The Events instance that handles events.
+ * @implements {ol.event.ISequence}
+ * @export
+ */
+ol.event.Scroll = function(target) {    
+    var element = target.getElement(),
+        handler = new goog.events.MouseWheelHandler(element);
+
+    /**
+     * @private
+     * @type {goog.events.MouseWheelHandler}
+     */
+    this.handler_ = handler;
+    
+    goog.events.listen(handler,
+        goog.events.MouseWheelHandler.EventType.MOUSEWHEEL,
+        function(evt) {
+            evt.type = 'scroll';
+            evt.target = element;
+            target.triggerEvent(evt.type, evt);
+        }
+    );
+};
+
+/** @inheritDoc */
+ol.event.Scroll.prototype.destroy = function() {
+    this.handler_.dispose();
+};
+
+
+ol.event.addSequenceProvider('scroll', ol.event.Scroll);