Implement Object.prototype.{hasOwnProperty, propertyIsEnumerable} for proxies.

src/proxy.js

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 118 matching lines @@
     writable: true,
     enumerable: true,
     configurable: true});
   return true;
 }
 
 function DerivedHasTrap(name) {
   return !!this.getPropertyDescriptor(name)
 }
 
+function DerivedHasOwnTrap(name) {
+  return !!this.getOwnPropertyDescriptor(name)
+}
+
 function DerivedKeysTrap() {
   var names = this.getOwnPropertyNames()
   var enumerableNames = []
   for (var i = 0, count = 0; i < names.length; ++i) {
     var name = names[i]
     if (this.getOwnPropertyDescriptor(TO_STRING_INLINE(name)).enumerable) {
       enumerableNames[count++] = names[i]
     }
   }
   return enumerableNames
 }