Clean up native context slots and add new ones.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 43c0f8aac780d007b07a076a906458f8fa3aaefc..de47c849480634bb8560a5289cf5e5f2cdd46ecd 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -1250,18 +1250,15 @@ Handle<Object> Factory::NewError(const char* maker, const char* message,
 }
 
 
-Handle<Object> Factory::NewError(const char* constructor,
+Handle<Object> Factory::NewError(Handle<JSFunction> constructor,
                                  Handle<String> message) {
-  Handle<String> constr = InternalizeUtf8String(constructor);
-  Handle<JSFunction> fun = Handle<JSFunction>::cast(Object::GetProperty(
-      isolate()->js_builtins_object(), constr).ToHandleChecked());
   Handle<Object> argv[] = { message };
 
   // Invoke the JavaScript factory method. If an exception is thrown while
   // running the factory method, use the exception as the result.
   Handle<Object> result;
   MaybeHandle<Object> exception;
-  if (!Execution::TryCall(fun, undefined_value(), arraysize(argv), argv,
+  if (!Execution::TryCall(constructor, undefined_value(), arraysize(argv), argv,
                           &exception)
            .ToHandle(&result)) {
     Handle<Object> exception_obj;