Promote createTileCoordTransform into base class

src/ol/tilegrid/tilegrid.js

@@ -102,6 +102,15 @@ ol.tilegrid.TileGrid = function(options) {
 ol.tilegrid.TileGrid.tmpTileCoord_ = new ol.TileCoord(0, 0, 0);
 
 
+/**
+ * @param {{extent: (ol.Extent|undefined),
+ *          wrapX: (boolean|undefined)}=} opt_options Options.
+ * @return {function(ol.TileCoord, ol.Projection, ol.TileCoord=): ol.TileCoord}
+ *     Tile coordinate transform.
+ */
+ol.tilegrid.TileGrid.prototype.createTileCoordTransform = goog.abstractMethod;
+
+
 /**
  * @param {ol.TileCoord} tileCoord Tile coordinate.
  * @param {function(this: T, number, ol.TileRange): boolean} callback Callback.

src/ol/tilegrid/xyztilegrid.js

@@ -37,10 +37,7 @@ goog.inherits(ol.tilegrid.XYZ, ol.tilegrid.TileGrid);
 
 
 /**
- * @param {{wrapX: (boolean|undefined),
- *          extent: (ol.Extent|undefined)}=} opt_options Options.
- * @return {function(ol.TileCoord, ol.Projection, ol.TileCoord=): ol.TileCoord}
- *     Tile coordinate transform.
+ * @inheritDoc
  */
 ol.tilegrid.XYZ.prototype.createTileCoordTransform = function(opt_options) {
   var options = goog.isDef(opt_options) ? opt_options : {};