code: private void addPropertiesConfigObjectReflection(
        PolymerClassDefinition cls, Node propertiesLiteral) {
      checkNotNull(propertiesLiteral);
      checkState(propertiesLiteral.isObjectLit());
  
      Node parent = propertiesLiteral.getParent();
  
      Node objReflectCall =
          IR.call(
                  NodeUtil.newQName(compiler, "$jscomp.reflectObject"),
                  cls.target.cloneTree(),
                  propertiesLiteral.detach())
              .useSourceInfoIfMissingFromForTree(propertiesLiteral);
      parent.addChildToFront(objReflectCall);
      compiler.reportChangeToEnclosingScope(parent);
    }
docs: Wrap the properties config object in an objectReflect call