Tile renderers needn't listen for tile change

src/ol/renderer/layerrenderer.js

@@ -41,12 +41,6 @@ ol.renderer.Layer = function(mapRenderer, layer) {
    */
   this.layer_ = layer;
 
-  /**
-   * @protected
-   * @type {Object.<string, boolean>}
-   */
-  this.observedTileKeys = {};
-
   goog.events.listen(this.layer_,
       ol.Object.getChangedEventType(ol.layer.LayerProperty.BRIGHTNESS),
       this.handleLayerBrightnessChange, false, this);
@@ -181,22 +175,6 @@ ol.renderer.Layer.prototype.handleTileChange_ = function(event) {
   if (tile.getState() === ol.TileState.LOADED) {
     this.getMap().requestRenderFrame();
   }
-  delete this.observedTileKeys[tile.getKey()];
-};
-
-
-/**
- * Listen once to tileKey, le change event.
- * @param {ol.Tile} tile Tile.
- * @protected
- */
-ol.renderer.Layer.prototype.listenToTileChange = function(tile) {
-  var tileKey = tile.getKey();
-  if (!(tileKey in this.observedTileKeys)) {
-    this.observedTileKeys[tileKey] = true;
-    goog.events.listenOnce(tile, goog.events.EventType.CHANGE,
-        this.handleTileChange_, false, this);
-  }
 };