Reuse existing canvases from vector render tiles

src/ol/Tile.js

@@ -144,6 +144,12 @@ class Tile extends EventTarget {
     this.dispatchEvent(EventType.CHANGE);
   }
 
+  /**
+   * Called by the tile cache when the tile is removed from the cache due to expiry
+   */
+  release() {
+  }
+
   /**
    * @return {string} Key.
    */