Async: add sh_ptr<ContinuationChainLink> to Callback<>

This change enables us to finally implement the tracing of
continuations backward from the point of acquisition for deadlock
debugging.

smocore/include/component.h

@@ -4,6 +4,7 @@
 #include <config.h>
 #include <memory>
 #include <functional>
+#include <callback.h>
 
 namespace smo {
 
@@ -44,8 +45,8 @@ public:
 
 public:
 	typedef std::function<void(bool)> mrnttLifetimeMgmtOpCbFn;
-	void initializeReq(mrnttLifetimeMgmtOpCbFn callback);
-	void finalizeReq(mrnttLifetimeMgmtOpCbFn callback);
+	void initializeReq(Callback<mrnttLifetimeMgmtOpCbFn> callback);
+	void finalizeReq(Callback<mrnttLifetimeMgmtOpCbFn> callback);
 
 private:
 	class MrnttLifetimeMgmtOp;