fixes for optional key handling

src/ol/source/TileImage.js

@@ -83,7 +83,8 @@ class TileImage extends UrlTile {
       url: options.url,
       urls: options.urls,
       wrapX: options.wrapX,
-      transition: options.transition
+      transition: options.transition,
+      opt_key: options.opt_key,
     });
 
     /**

src/ol/source/UrlTile.js

@@ -64,6 +64,7 @@ class UrlTile extends TileSource {
      */
     this.tileUrlFunction = this.fixedTileUrlFunction ?
       this.fixedTileUrlFunction.bind(this) : nullTileUrlFunction;
+    this.key_ = options.opt_key || this.key_;
 
     /**
      * @protected
@@ -77,7 +78,7 @@ class UrlTile extends TileSource {
       this.setUrl(options.url);
     }
     if (options.tileUrlFunction) {
-      this.setTileUrlFunction(options.tileUrlFunction);
+      this.setTileUrlFunction(options.tileUrlFunction, options.opt_key);
     }
 
     /**