add drag gesture event.

dom/public/coreEvents/nsIDOMDragListener.h

@@ -65,6 +65,13 @@ public:
    * @returns whether the event was consumed or ignored. @see nsresult
    */
   virtual nsresult DragDrop(nsIDOMEvent* aMouseEvent) = 0;
+  
+  /**
+   * Processes a drag gesture event
+   * @param aMouseEvent @see nsIDOMEvent.h 
+   * @returns whether the event was consumed or ignored. @see nsresult
+   */
+  virtual nsresult DragGesture(nsIDOMEvent* aMouseEvent) = 0;
 
 };
 

widget/public/nsGUIEvent.h

@@ -313,6 +313,7 @@ enum nsDragDropEventStatus {
 #define NS_DRAGDROP_OVER                (NS_DRAGDROP_EVENT_START + 1)
 #define NS_DRAGDROP_EXIT                (NS_DRAGDROP_EVENT_START + 2)
 #define NS_DRAGDROP_DROP                (NS_DRAGDROP_EVENT_START + 3)
+#define NS_DRAGDROP_GESTURE             (NS_DRAGDROP_EVENT_START + 4)
 
 // Events for popups
 #define NS_MENU_EVENT_START            1500