Factor out ImageTile and ImageTileSource

src/ol/source/tilesource.js

@@ -14,11 +14,9 @@ goog.require('ol.tilegrid.TileGrid');
 
 /**
  * @typedef {{attributions: (Array.<ol.Attribution>|undefined),
- *            crossOrigin: (null|string|undefined),
  *            extent: (ol.Extent|undefined),
  *            projection: (ol.Projection|undefined),
- *            tileGrid: (ol.tilegrid.TileGrid|undefined),
- *            tileUrlFunction: (ol.TileUrlFunctionType|undefined)}}
+ *            tileGrid: (ol.tilegrid.TileGrid|undefined)}}
  */
 ol.source.TileSourceOptions;
 
@@ -44,29 +42,6 @@ ol.source.TileSource = function(tileSourceOptions) {
   this.tileGrid = goog.isDef(tileSourceOptions.tileGrid) ?
       tileSourceOptions.tileGrid : null;
 
-  /**
-   * @protected
-   * @type {ol.TileUrlFunctionType}
-   */
-  this.tileUrlFunction = goog.isDef(tileSourceOptions.tileUrlFunction) ?
-      tileSourceOptions.tileUrlFunction :
-      ol.TileUrlFunction.nullTileUrlFunction;
-
-  /**
-   * @private
-   * @type {?string}
-   */
-  this.crossOrigin_ = goog.isDef(tileSourceOptions.crossOrigin) ?
-      tileSourceOptions.crossOrigin : 'anonymous';
-
-  /**
-   * @private
-   * @type {Object.<string, ol.Tile>}
-   * FIXME will need to expire elements from this cache
-   * FIXME see elemoine's work with goog.structs.LinkedMap
-   */
-  this.tileCache_ = {};
-
 };
 goog.inherits(ol.source.TileSource, ol.source.Source);
 
@@ -83,31 +58,7 @@ ol.source.TileSource.prototype.getResolutions = function() {
  * @param {ol.TileCoord} tileCoord Tile coordinate.
  * @return {ol.Tile} Tile.
  */
-ol.source.TileSource.prototype.getTile = function(tileCoord) {
-  var key = tileCoord.toString();
-  if (goog.object.containsKey(this.tileCache_, key)) {
-    return this.tileCache_[key];
-  } else {
-    var tileUrl = this.getTileCoordUrl(tileCoord);
-    var tile;
-    if (goog.isDef(tileUrl)) {
-      tile = new ol.Tile(tileCoord, tileUrl, this.crossOrigin_);
-    } else {
-      tile = null;
-    }
-    this.tileCache_[key] = tile;
-    return tile;
-  }
-};
-
-
-/**
- * @param {ol.TileCoord} tileCoord Tile coordinate.
- * @return {string|undefined} Tile URL.
- */
-ol.source.TileSource.prototype.getTileCoordUrl = function(tileCoord) {
-  return this.tileUrlFunction(tileCoord);
-};
+ol.source.TileSource.prototype.getTile = goog.abstractMethod;
 
 
 /**