allowLateRegistration() {
    if (ENABLE_ASSERTS) {
      /** @type {!DelegateRegistryBase} */ (this).allowLateRegistration_ = true;
    }
    return /** @type {?} */ (this);
  }
Configures this registry to allow late registration.  Normally it is an
error to register a delegate after calling `delegate()` or `delegates()`.
If late registration is allowed, then this is no longer an error.  This
check only ever happens in debug mode.  Returns this.
@return {THIS}
@this {THIS}
@template THIS