Update stub.js

add support for toJSON for LatLngBounds

Author: tofucubes

stub.js

@@ -55,6 +55,12 @@ window.google = {
       return {
         getSouthWest: function() { return sw; },
         getNorthEast: function() { return ne; },
+        toJSON: () => ({
+            south: sw ? (sw.lat || sw.latitude) : 0,
+            north: ne ? (ne.lat || ne.latitude) : 0,
+            west: sw ? (sw.lng || sw.longitude) : 0,
+            east: ne ? (ne.lng || ne.longitude) : 0,
+        }),
       };
     },
     Map: function() {