Use Array.isArray instead of goog.isArray

src/ol/source/imagevectorsource.js

@@ -264,7 +264,7 @@ ol.source.ImageVector.prototype.renderFeature_ = function(feature, resolution, p
     return false;
   }
   var i, ii, loading = false;
-  if (!goog.isArray(styles)) {
+  if (!Array.isArray(styles)) {
     styles = [styles];
   }
   for (i = 0, ii = styles.length; i < ii; ++i) {

src/ol/source/vectorsource.js

@@ -172,7 +172,7 @@ ol.source.Vector = function(opt_options) {
   if (options.features instanceof ol.Collection) {
     collection = options.features;
     features = collection.getArray();
-  } else if (goog.isArray(options.features)) {
+  } else if (Array.isArray(options.features)) {
     features = options.features;
   }
   if (!useSpatialIndex && collection === undefined) {