Add associates() method to state objects

Change-Id: Ie62455b7b73424502ac01e2534482a3db99225ff
diff --git a/dev/js/spec/stateSpec.js b/dev/js/spec/stateSpec.js
index 865691e..6a2f32a 100644
--- a/dev/js/spec/stateSpec.js
+++ b/dev/js/spec/stateSpec.js
@@ -34,14 +34,17 @@
           this.x = value;
         }
       };
-      
+
+      expect(s.associates()).toEqual(0);
       expect(s.get()).toBeFalsy();
       expect(obj1.x).toBeFalsy();
       expect(obj2.x).toBeTruthy();
 
       // Associate object with state
       s.associate(obj1);
+      expect(s.associates()).toEqual(1);
       s.associate(obj2);
+      expect(s.associates()).toEqual(2);
 
       expect(s.get()).toBeFalsy();
       expect(obj1.x).toBeFalsy();