code: public static Callable getPropFunctionAndThis(Object obj,
                                                    String property,
                                                    Context cx, Scriptable scope)
      {
          Scriptable thisObj = toObjectOrNull(cx, obj, scope);
          return getPropFunctionAndThisHelper(obj, property, cx, thisObj);
      }
docs: Prepare for calling obj.property(...): return function corresponding to
  obj.property and make obj properly converted to Scriptable available
  as ScriptRuntime.lastStoredScriptable() for consumption as thisObj.
  The caller must call ScriptRuntime.lastStoredScriptable() immediately
  after calling this method.