mgmt: Switch nfd::Controller to use v2::Validator interface

The conversion also includes relevant changes in SegmentFetcher and
tests.

Change-Id: Ie2f55bac650e3689f4971ab814a8bd51068a2a40
Refs: #3920
diff --git a/src/security/validator-null.cpp b/src/security/validator-null.cpp
new file mode 100644
index 0000000..6ca3174
--- /dev/null
+++ b/src/security/validator-null.cpp
@@ -0,0 +1,44 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2017 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#include "validator-null.hpp"
+#include "v2/validation-policy-accept-all.hpp"
+#include "v2/certificate-fetcher-offline.hpp"
+
+namespace ndn {
+namespace security {
+namespace v2 {
+
+ValidatorNull::ValidatorNull()
+  : Validator(make_unique<ValidationPolicyAcceptAll>(), make_unique<CertificateFetcherOffline>())
+{
+}
+
+security::v2::Validator&
+getAcceptAllValidator()
+{
+  static security::ValidatorNull validator;
+  return validator;
+}
+
+} // namespace v2
+} // namespace security
+} // namespace ndn