give tiles a reference back to their container OpenLayers.Grid

git-svn-id: http://svn.openlayers.org/trunk/openlayers@180 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Tile.js

@@ -10,6 +10,9 @@
 OpenLayers.Tile = Class.create();
 OpenLayers.Tile.prototype = {
     
+    /** @type OpenLayers.Grid */
+    grid: null,
+    
     // str - url of the request
     url:null,
 
@@ -23,11 +26,16 @@ OpenLayers.Tile.prototype = {
     position:null,
 
     /**
-    * @param {OpenLayers.Layer} layer
-    * @param {OpenLayers.LonLat} coord
+    * @constructor
+    *
+    * @param {OpenLayers.Grid} grid
+    * @param {OpenLayers.Bounds} bounds
+    * @param {String} url
+    * @param {OpenLayers.Size} size
     */   
-    initialize: function(bounds,url,size) {
+    initialize: function(grid, bounds, url, size) {
         if (arguments.length > 0) {
+            this.grid = grid;
             this.url = url;
             this.bounds = bounds;
             this.size = size;