Helper function to install a getter-only accessor property.
function InstallGetter(object, name, getter, attributes, prefix) {
  %CheckIsBootstrapping();
  if (IS_UNDEFINED(attributes)) attributes = DONT_ENUM;
  SetFunctionName(getter, name, IS_UNDEFINED(prefix) ? "get" : prefix);
  %FunctionRemovePrototype(getter);
  %DefineGetterPropertyUnchecked(object, name, getter, attributes);
  %SetNativeFlag(getter);
}