| Index: src/isolate.cc | 
| diff --git a/src/isolate.cc b/src/isolate.cc | 
| index d5cda54a1859fac6cccb6b7e8bad31c340fb03d5..a3456c4600212a99cd1ec0eb3b9320f3e303b2ae 100644 | 
| --- a/src/isolate.cc | 
| +++ b/src/isolate.cc | 
| @@ -1348,21 +1348,14 @@ bool Isolate::ComputeLocationFromStackTrace(MessageLocation* target, | 
| } | 
|  | 
|  | 
| -// Traverse prototype chain to find out whether the object is derived from | 
| -// the Error object. | 
| -bool Isolate::IsErrorObject(Handle<Object> obj) { | 
| -  if (!obj->IsJSObject()) return false; | 
| -  Handle<Object> error_constructor = error_function(); | 
| -  DisallowHeapAllocation no_gc; | 
| -  for (PrototypeIterator iter(this, *obj, PrototypeIterator::START_AT_RECEIVER); | 
| -       !iter.IsAtEnd(); iter.Advance()) { | 
| -    if (iter.GetCurrent()->IsJSProxy()) return false; | 
| -    if (iter.GetCurrent<JSObject>()->map()->GetConstructor() == | 
| -        *error_constructor) { | 
| -      return true; | 
| -    } | 
| -  } | 
| -  return false; | 
| +// Use stack_trace_symbol as proxy for [[ErrorData]]. | 
| +bool Isolate::IsErrorObject(Handle<Object> object) { | 
| +  Handle<Name> symbol = factory()->stack_trace_symbol(); | 
| +  if (!object->IsJSObject()) return false; | 
| +  Maybe<bool> has_stack_trace = | 
| +      JSReceiver::HasOwnProperty(Handle<JSReceiver>::cast(object), symbol); | 
| +  DCHECK(!has_stack_trace.IsNothing()); | 
| +  return has_stack_trace.FromJust(); | 
| } | 
|  | 
|  | 
|  |