Port r9030 and part of r9016 to 3.3 branch.

src/v8natives.js

 // Copyright 2006-2008 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 308 matching lines @@
 }
 
 
 function IsInconsistentDescriptor(desc) {
   return IsAccessorDescriptor(desc) && IsDataDescriptor(desc);
 }
 
 // ES5 8.10.4
 function FromPropertyDescriptor(desc) {
   if (IS_UNDEFINED(desc)) return desc;
-  var obj = new $Object();
+
   if (IsDataDescriptor(desc)) {
-    obj.value = desc.getValue();
-    obj.writable = desc.isWritable();
+    return { value: desc.getValue(),
+             writable: desc.isWritable(),
+             enumerable: desc.isEnumerable(),
+             configurable: desc.isConfigurable() };
   }
-  if (IsAccessorDescriptor(desc)) {
-    obj.get = desc.getGet();
-    obj.set = desc.getSet();
-  }
-  obj.enumerable = desc.isEnumerable();
-  obj.configurable = desc.isConfigurable();
-  return obj;
+  // Must be an AccessorDescriptor then. We never return a generic descriptor.
+  return { get: desc.getGet(),
+           set: desc.getSet(),
+           enumerable: desc.isEnumerable(),
+           configurable: desc.isConfigurable() };
 }
 
 // ES5 8.10.5.
 function ToPropertyDescriptor(obj) {
   if (!IS_SPEC_OBJECT(obj)) {
     throw MakeTypeError("property_desc_object", [obj]);
   }
   var desc = new PropertyDescriptor();
 
   if ("enumerable" in obj) {
@@ skipping 951 matching lines @@
 // ----------------------------------------------------------------------------
 
 function SetupFunction() {
   InstallFunctions($Function.prototype, DONT_ENUM, $Array(
     "bind", FunctionBind,
     "toString", FunctionToString
   ));
 }
 
 SetupFunction();