Use Host Command Manager in host interface implementation

Change-Id: Icefce510a3a0022bf0288fa99518459b732a2e04
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/timer.hpp b/timer.hpp
index cbd3444..6a59c0d 100644
--- a/timer.hpp
+++ b/timer.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <chrono>
 #include <functional>
 #include <systemd/sd-event.h>
 namespace phosphor