domain: dry decorate using util._extend

lib/domain.js

@@ -53,7 +53,7 @@ function uncaughtHandler(er) {
   // if there's an active domain, then handle this there.
   // Note that if this error emission throws, then it'll just crash.
   if (exports.active && !exports.active._disposed) {
-    decorate(er, {
+    util._extend(er, {
       domain: exports.active,
       domain_thrown: true
     });
@@ -158,7 +158,7 @@ Domain.prototype.bind = function(cb, interceptError) {
     if (interceptError && arguments[0] &&
         (arguments[0] instanceof Error)) {
       var er = arguments[0];
-      decorate(er, {
+      util._extend(er, {
         domain_bound: cb,
         domain_thrown: false,
         domain: self
@@ -251,11 +251,3 @@ Domain.prototype.dispose = function() {
   // so that it can't be entered or activated.
   this._disposed = true;
 };
-
-
-function decorate(er, props) {
-  Object.keys(props).forEach(function(k, _, __) {
-    if (er.hasOwnProperty(k)) return;
-    er[k] = props[k];
-  });
-}