Activating strategies after adding the layer to the map. r=elemoine (closes #1920)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@9266 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer.js

@@ -529,6 +529,14 @@ OpenLayers.Layer = OpenLayers.Class({
         }
     },
     
+    /**
+     * Method: afterAdd
+     * Called at the end of the map.addLayer sequence.  At this point, the map
+     *     will have a base layer.  To be overridden by subclasses.
+     */
+    afterAdd: function() {
+    },
+    
     /**
      * APIMethod: removeMap
      * Just as setMap() allows each layer the possibility to take a 

lib/OpenLayers/Layer/Vector.js

@@ -350,6 +350,15 @@ OpenLayers.Layer.Vector = OpenLayers.Class(OpenLayers.Layer, {
             this.renderer.map = this.map;
             this.renderer.setSize(this.map.getSize());
         }
+    },
+
+    /**
+     * Method: afterAdd
+     * Called at the end of the map.addLayer sequence.  At this point, the map
+     *     will have a base layer.  Any autoActivate strategies will be
+     *     activated here.
+     */
+    afterAdd: function() {
         if(this.strategies) {
             var strategy, i, len;
             for(i=0, len=this.strategies.length; i<len; i++) {

lib/OpenLayers/Map.js

@@ -926,6 +926,7 @@ OpenLayers.Map = OpenLayers.Class({
         }
 
         this.events.triggerEvent("addlayer", {layer: layer});
+        layer.afterAdd();
     },
 
     /**

tests/Layer.html

@@ -454,6 +454,21 @@
              "(fractionalZoom true) returns resolution for zoom beyond res length - 1");
         
     }
+    
+    function test_afterAdd(t) {
+        
+        t.plan(1);
+        
+        var map = new OpenLayers.Map("map");
+        var layer = new OpenLayers.Layer(null, {isBaseLayer: true});
+        var hasBase = false;
+        layer.afterAdd = function() {
+            hasBase = !!(layer.map && layer.map.baseLayer);
+        }
+        map.addLayer(layer);
+        t.eq(hasBase, true, "when afterAdd is called, map has a base layer");
+        
+    }