Allow the use of custom GMapTypes via the Layer.Google. When passed a type in

the Layer.Google constructor, we check if the type we are given is not in the
map's list of types, and if so, add it. (Closes #1082) 
r=tschaub 


git-svn-id: http://svn.openlayers.org/trunk/openlayers@5504 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Google.js

@@ -159,6 +159,13 @@ OpenLayers.Layer.Google = OpenLayers.Class(
      */
     setMapType: function() {
         if (this.mapObject.getCenter() != null) {
+            
+            // Support for custom map types.
+            if (OpenLayers.Util.indexOf(this.mapObject.getMapTypes(),
+                                        this.type) == -1) {
+                this.mapObject.addMapType(this.type);
+            }    
+
             this.mapObject.setMapType(this.type);
             this.map.events.unregister("moveend", this, this.setMapType);
         }