Use instance type in Object::IsErrorObject().

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 15da7353b87cc478130e93bf9b4642cb33dc393a..0b1d8982ba33bbbd0ce93d9f8272be3e377a9d07 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -1287,18 +1287,6 @@ Maybe<bool> Object::SetPropertyWithDefinedSetter(Handle<Object> receiver,
 
 
 // static
-bool Object::IsErrorObject(Isolate* isolate, Handle<Object> object) {
-  if (!object->IsJSObject()) return false;
-  // Use stack_trace_symbol as proxy for [[ErrorData]].
-  Handle<Name> symbol = isolate->factory()->stack_trace_symbol();
-  Maybe<bool> has_stack_trace =
-      JSReceiver::HasOwnProperty(Handle<JSReceiver>::cast(object), symbol);
-  DCHECK(!has_stack_trace.IsNothing());
-  return has_stack_trace.FromJust();
-}
-
-
-// static
 bool JSObject::AllCanRead(LookupIterator* it) {
   // Skip current iteration, it's in state ACCESS_CHECK or INTERCEPTOR, both of
   // which have already been checked.