Fix behavior of oneshot accessors of error objects.

src/messages.js

 // Copyright 2012 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 750 matching lines @@
 
 function GetStackTraceLine(recv, fun, pos, isGlobal) {
   return new CallSite(recv, fun, pos).toString();
 }
 
 // ----------------------------------------------------------------------------
 // Error implementation
 
 // Defines accessors for a property that is calculated the first time
 // the property is read.
-function DefineOneShotAccessor(obj, name, fun) {
-  // Note that the accessors consistently operate on 'obj', not 'this'.
-  // Since the object may occur in someone else's prototype chain we
-  // can't rely on 'this' being the same as 'obj'.
-  var value;
-  var value_factory = fun;
+function DefineOneShotAccessor(obj, name, value_factory) {
+  // Note that 'obj' may be different than 'this' since obj may be on the
+  // prototype chain of 'this'.
   var getter = function() {
-    if (value_factory == null) {
-      return value;
-    }
-    value = value_factory(obj);
-    value_factory = null;
+    var value = value_factory(obj);
+    delete obj[name];
+    obj[name] = value;
     return value;
   };
   var setter = function(v) {
-    value_factory = null;
-    value = v;
+    // Set the property for 'this', ignoring this setter.
+    %DefineOrRedefineDataProperty(this, name, v, NONE);
   };
   %DefineOrRedefineAccessorProperty(obj, name, getter, setter, DONT_ENUM);
 }
 
 function CallSite(receiver, fun, pos) {
   this.receiver = receiver;
   this.fun = fun;
   this.pos = pos;
 }
 
@@ skipping 467 matching lines @@
     throw e;
   }
 }
 
 
 InstallFunctions($Error.prototype, DONT_ENUM, ['toString', ErrorToString]);
 
 // Boilerplate for exceptions for stack overflows. Used from
 // Isolate::StackOverflow().
 var kStackOverflowBoilerplate = MakeRangeError('stack_overflow', []);