Move ol.DRAGZOOM_ANIMATION_DURATION const to a constructor option

externs/olx.js

@@ -2286,6 +2286,7 @@ olx.interaction.DragRotateOptions.prototype.condition;
 
 /**
  * @typedef {{condition: (ol.events.ConditionType|undefined),
+ *     duration: (number|undefined),
  *     style: ol.style.Style}}
  * @api
  */
@@ -2302,6 +2303,14 @@ olx.interaction.DragZoomOptions;
 olx.interaction.DragZoomOptions.prototype.condition;
 
 
+/**
+ * Animation duration in milliseconds. Default is `200`.
+ * @type {number|undefined}
+ * @api
+ */
+olx.interaction.DragZoomOptions.prototype.duration;
+
+
 /**
  * Style for the box.
  * @type {ol.style.Style}

src/ol/interaction/dragzoominteraction.js

@@ -1,7 +1,6 @@
 goog.provide('ol.interaction.DragZoom');
 
 goog.require('goog.asserts');
-goog.require('ol');
 goog.require('ol.events.condition');
 goog.require('ol.extent');
 goog.require('ol.interaction.DragBox');
@@ -28,6 +27,12 @@ ol.interaction.DragZoom = function(opt_options) {
   var condition = goog.isDef(options.condition) ?
       options.condition : ol.events.condition.shiftKeyOnly;
 
+  /**
+   * @private
+   * @type {number}
+   */
+  this.duration_ = goog.isDef(options.duration) ? options.duration : 200;
+
   /**
    * @private
    * @type {ol.style.Style}
@@ -61,5 +66,5 @@ ol.interaction.DragZoom.prototype.onBoxEnd = function() {
   goog.asserts.assert(goog.isDef(size), 'size should be defined');
   ol.interaction.Interaction.zoom(map, view,
       view.getResolutionForExtent(extent, size),
-      center, ol.DRAGZOOM_ANIMATION_DURATION);
+      center, this.duration_);
 };

src/ol/ol.js

@@ -60,12 +60,6 @@ ol.DRAGROTATEANDZOOM_ANIMATION_DURATION = 400;
 ol.DRAGROTATE_ANIMATION_DURATION = 250;
 
 
-/**
- * @define {number} Drag-zoom animation duration.
- */
-ol.DRAGZOOM_ANIMATION_DURATION = 200;
-
-
 /**
  * @define {number} Hysteresis pixels.
  */