Merge pull request #4176 from tschaub/remove-isdefandnotnull

Remove use of goog.isDefAndNotNull().

src/ol/render/webgl/webglimmediate.js

@@ -125,7 +125,7 @@ ol.render.webgl.Immediate.prototype.drawCircleGeometry =
  */
 ol.render.webgl.Immediate.prototype.drawFeature = function(feature, style) {
   var geometry = style.getGeometryFunction()(feature);
-  if (!goog.isDefAndNotNull(geometry) ||
+  if (!geometry ||
       !ol.extent.intersects(this.extent_, geometry.getExtent())) {
     return;
   }

src/ol/render/webgl/webglreplay.js

@@ -821,7 +821,7 @@ ol.render.webgl.ImageReplay.prototype.drawHitDetectionReplayOneByOne_ =
       featureUid = goog.getUid(feature).toString();
 
       if (skippedFeaturesHash[featureUid] === undefined &&
-          goog.isDefAndNotNull(feature.getGeometry()) &&
+          feature.getGeometry() &&
           (opt_hitExtent === undefined || ol.extent.intersects(
               /** @type {Array<number>} */ (opt_hitExtent),
               feature.getGeometry().getExtent()))) {