Add a basic geometry interface

src/ol/geom/IGeometry.js

@@ -0,0 +1,27 @@
+goog.provide('ol.geom.IGeometry');
+
+//goog.require('ol.geom.Point');
+//goog.require('ol.Bounds');
+
+/**
+ * Interface for geometry classes forcing ol.geom.* classes to implement 
+ * expected functionality.
+ * 
+ * @interface
+ */
+ol.geom.IGeometry = function(){};
+
+/**
+ * @return {ol.geom.Point} The centroid of the geometry.
+ */
+ol.geom.IGeometry.prototype.getCentroid = function(){};
+
+/**
+ * @return {ol.Bounds|undefined} The centroid of the geometry.
+ */
+ol.geom.IGeometry.prototype.getBounds = function(){};
+
+/**
+ * @return {number} The area of the geometry.
+ */
+ol.geom.IGeometry.prototype.getArea = function(){};