using blank image to avoid the "Loading Image" frames on Firefox that were discussed during the review (see #3419)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@12243 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Tile/Image/IFrame.js

@@ -28,15 +28,7 @@ OpenLayers.Tile.Image.IFrame = {
      */ 
     useIFrame: null,
 
-    /**
-     * Property: blankImageUrl
-     * {String} This is only used as background image for the eventPane, so we
-     * don't care that this doesn't actually result in a blank image on all
-     * browsers
-     */
-    blankImageUrl: "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAQAIBRAA7",
-
-    /**
+   /**
     * Method: updateBackBuffer
     * Update the <backBufferData>, and return a new or reposition the
     * backBuffer. When a backbuffer is returned, the tile's markup is not
@@ -193,4 +185,4 @@ OpenLayers.Tile.Image.IFrame = {
         }
     }
 
-};
+};