Add drag box in shift drag zoom control

src/ol/interaction/shiftdragzoom.js

@@ -4,6 +4,7 @@ goog.provide('ol.interaction.ShiftDragZoom');
 
 goog.require('ol.Extent');
 goog.require('ol.MapBrowserEvent');
+goog.require('ol.control.DragBox');
 goog.require('ol.interaction.Drag');
 
 
@@ -27,7 +28,16 @@ ol.SHIFT_DRAG_ZOOM_HYSTERESIS_PIXELS_SQUARED =
  * @extends {ol.interaction.Drag}
  */
 ol.interaction.ShiftDragZoom = function() {
+
   goog.base(this);
+
+  /**
+   * @type {ol.control.DragBox}
+   * @private
+   */
+  this.dragBox_ = null;
+
+
 };
 goog.inherits(ol.interaction.ShiftDragZoom, ol.interaction.Drag);
 
@@ -37,6 +47,8 @@ goog.inherits(ol.interaction.ShiftDragZoom, ol.interaction.Drag);
  */
 ol.interaction.ShiftDragZoom.prototype.handleDragEnd =
     function(mapBrowserEvent) {
+  this.dragBox_.setMap(null);
+  this.dragBox = null;
   if (this.deltaX * this.deltaX + this.deltaY * this.deltaY >=
       ol.SHIFT_DRAG_ZOOM_HYSTERESIS_PIXELS_SQUARED) {
     var map = mapBrowserEvent.map;
@@ -55,6 +67,10 @@ ol.interaction.ShiftDragZoom.prototype.handleDragStart =
     function(mapBrowserEvent) {
   var browserEvent = mapBrowserEvent.browserEvent;
   if (browserEvent.isMouseActionButton() && browserEvent.shiftKey) {
+    this.dragBox_ = new ol.control.DragBox({
+      map: mapBrowserEvent.map,
+      startCoordinate: this.startCoordinate
+    });
     return true;
   } else {
     return false;