Use version 20150920 of Closure Compiler

closure-util.json

@@ -1,3 +1,3 @@
 {
-  "library_url": "https://github.com/google/closure-library/archive/a5f9b8a.zip"
+  "library_url": "https://github.com/google/closure-library/archive/5b25e65.zip"
 }

package.json

@@ -27,7 +27,7 @@
   "dependencies": {
     "async": "0.9.0",
     "browserify": "9.0.3",
-    "closure-util": "1.7.0",
+    "closure-util": "1.8.0",
     "fs-extra": "0.12.0",
     "glob": "5.0.3",
     "graceful-fs": "3.0.2",

src/ol/ol.js

@@ -232,8 +232,8 @@ ol.WEBGL_EXTENSIONS; // value is set in `ol.has`
  *       // Other code here.
  *     };
  *
- * @param {Function} childCtor Child constructor.
- * @param {Function} parentCtor Parent constructor.
+ * @param {!Function} childCtor Child constructor.
+ * @param {!Function} parentCtor Parent constructor.
  * @function
  * @api
  */