add an OSM layer constructor to the API

src/api/layer/osm.js

@@ -0,0 +1,9 @@
+goog.provide('ol.layer.osm');
+
+/**
+ * @export
+ * @return {ol.layer.OSM}
+ */
+ol.layer.osm = function() {
+    return new ol.layer.OSM();
+};

src/ol.js

@@ -10,6 +10,7 @@ goog.require("ol.loc");
 goog.require("ol.feature");
 goog.require("ol.projection");
 goog.require("ol.layer.xyz");
+goog.require("ol.layer.osm");
 goog.require("ol.Tile");
 goog.require("ol.TileSet");
 goog.require("ol.geom.geometry");

test/index.html

@@ -53,6 +53,7 @@
   <script type="text/javascript" src="spec/api/map.test.js"></script>
   <script type="text/javascript" src="spec/api/projection.test.js"></script>
   <script type="text/javascript" src="spec/api/layer/xyz.test.js"></script>
+  <script type="text/javascript" src="spec/api/layer/osm.test.js"></script>
   <script type="text/javascript" src="spec/api/feature.test.js"></script>
   <script type="text/javascript" src="spec/ol/Events.test.js"></script>
   <script type="text/javascript" src="spec/ol/UnreferencedBounds.test.js"></script>

test/spec/api/layer/osm.test.js

@@ -0,0 +1,12 @@
+describe('ol.layer.osm', function() {
+
+    describe('create an OSM layer', function() {
+
+        it('returns an ol.layer.OSM instance', function() {
+            var layer = ol.layer.osm();
+            expect(layer).toBeA(ol.layer.OSM);
+        });
+
+    });
+
+});