base: add PacketBase to provide wrappers for congestion tags

refs #3797

Change-Id: I8747bb4fcbc11bfd1731516896b8aef1ec181c36
diff --git a/src/data.hpp b/src/data.hpp
index 2729e0d..e0a8466 100644
--- a/src/data.hpp
+++ b/src/data.hpp
@@ -24,15 +24,15 @@
 
 #include "meta-info.hpp"
 #include "name.hpp"
+#include "packet-base.hpp"
 #include "signature.hpp"
-#include "tag-host.hpp"
 #include "encoding/block.hpp"
 
 namespace ndn {
 
 /** @brief Represents a Data packet
  */
-class Data : public TagHost, public enable_shared_from_this<Data>
+class Data : public PacketBase, public enable_shared_from_this<Data>
 {
 public:
   class Error : public tlv::Error