Bump to v4.16.0.

_mapCacheSet.js

@@ -11,7 +11,11 @@ define(['./_getMapData'], function(getMapData) {
    * @returns {Object} Returns the map cache instance.
    */
   function mapCacheSet(key, value) {
-    getMapData(this, key).set(key, value);
+    var data = getMapData(this, key),
+        size = data.size;
+
+    data.set(key, value);
+    this.size += data.size == size ? 0 : 1;
     return this;
   }