Change getUrlAsync parameters.

Instead of giving the function a bound, a scope, a property to update
and a callback, only give the bound and a callback.

When the url is retrieved by getUrlAsync, simply call the callback
with the url as argument and let the caller manage this.

lib/OpenLayers/Layer/ArcIMS.js

@@ -205,12 +205,9 @@ OpenLayers.Layer.ArcIMS = OpenLayers.Class(OpenLayers.Layer.Grid, {
      * Parameters:
      * bounds - {<OpenLayers.Bounds>} A bounds representing the bbox for the
      *     request.
-     * scope - {Object} The scope of the callback method.
-     * prop - {String} The name of the property in the scoped object to 
-     *     recieve the image url.
      * callback - {Function} Function to call when image url is retrieved.
      */
-    getURLasync: function(bounds, scope, prop, callback) {
+    getURLasync: function(bounds, callback) {
         bounds = this.adjustBounds(bounds);
         
         // create an arcxml request to generate the image
@@ -239,11 +236,7 @@ OpenLayers.Layer.ArcIMS = OpenLayers.Class(OpenLayers.Layer.Grid, {
                 var axlResp = new OpenLayers.Format.ArcXML();
                 var arcxml = axlResp.read(doc);
                 
-                scope[prop] = this.getUrlOrImage(arcxml.image.output);
-
-                // call the callback function to recieve the updated property on the
-                // scoped object
-                callback.apply(scope);
+                callback(this.getUrlOrImage(arcxml.image.output));
             },
             scope: this
         });

lib/OpenLayers/Tile/Image.js

@@ -168,15 +168,14 @@ OpenLayers.Tile.Image = OpenLayers.Class(OpenLayers.Tile, {
         this.layer.div.appendChild(this.getTile());
         if (this.layer.async) {
             // Asynchronous image requests call the asynchronous getURL method
-            // on the layer to fetch an image that covers 'this.bounds', in the scope of
-            // 'this', setting the 'url' property of the layer itself, and running
-            // the callback 'initImage' when the image request returns.
-            var myId = this.asyncRequestId = (this.asyncRequestId || 0) + 1;
-            this.layer.getURLasync(this.bounds, this, "url", function() {
-                if (myId == this.asyncRequestId) {
+            // on the layer to fetch an image that covers 'this.bounds'.
+            var id = this.asyncRequestId = (this.asyncRequestId || 0) + 1;
+            this.layer.getURLasync(this.bounds, OpenLayers.Function.bind(function(url) {
+                if (id == this.asyncRequestId) {
+                    this.url = url;
                     this.initImage();
                 }
-            });
+            }, this));
         } else {
             // synchronous image requests get the url immediately.
             this.url = this.layer.getURL(this.bounds);

tests/Tile/Image.html

@@ -85,9 +85,8 @@
         var layer = new OpenLayers.Layer.WMS(
             "Name",
             "http://labs.metacarta.com/TESTURL?",
-            {layers: 'basic'}, {async: true, getURLasync: function(bounds, scope, url, callback) {
-                scope.url = this.getURL(bounds);
-                callback.call(scope);
+            {layers: 'basic'}, {async: true, getURLasync: function(bounds, callback) {
+                callback(this.getURL(bounds));
             }}
         ); 
         map.addLayer(layer);