util: Support MustBeFresh processing in InMemoryStorage

Change-Id: I8e8e647d7673e4e0fe8dd1c5025fbc8e5e524c70
Refs: #3274
diff --git a/src/util/in-memory-storage-lfu.hpp b/src/util/in-memory-storage-lfu.hpp
index ac8a02d..f02079e 100644
--- a/src/util/in-memory-storage-lfu.hpp
+++ b/src/util/in-memory-storage-lfu.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2013-2014 Regents of the University of California.
+ * Copyright (c) 2013-2016 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -43,6 +43,9 @@
   explicit
   InMemoryStorageLfu(size_t limit = 10);
 
+  explicit
+  InMemoryStorageLfu(boost::asio::io_service& ioService, size_t limit = 10);
+
   virtual
   ~InMemoryStorageLfu();