Re #933. Apply transition effect patch to trunk, many thanks to Erik, Tim and Chris for support. r=crschmidt, tschaub.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@6452 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -257,6 +257,26 @@ OpenLayers.Layer = OpenLayers.Class({
      */
     wrapDateLine: false,
     
+    /**
+     * APIProperty: transitionEffect
+     * {String} The transition effect to use when the map is panned or
+     *     zoomed.  
+     *
+     * There are currently two supported values:
+     *  - *null* No transition effect (the default).
+     *  - *resize*  Existing tiles are resized on zoom to provide a visual
+     *    effect of the zoom having taken place immediately.  As the
+     *    new tiles become available, they are drawn over top of the
+     *    resized tiles.
+     */
+    transitionEffect: null,
+    
+    /**
+     * Property: SUPPORTED_TRANSITIONS
+     * {Array} An immutable (that means don't change it!) list of supported 
+     *     transitionEffect values.
+     */
+    SUPPORTED_TRANSITIONS: ['resize'],
     
     /**
      * Constructor: OpenLayers.Layer