Trigger VPD recollection at standby

This commit implement changes to trigger VPD collection at
standby for FRUs which can be replaced at standby.

The recollection is trigerred when the Host current state is
set to "TransitioningToRunning". Implies the state between
Bmc standby state and Host running state.

signed-off-by: Sunny Srivastava <sunnsr25@in.ibm.com>
Change-Id: I9296c80df856afe9a9b1c64a5a01cb3727af5e3c
diff --git a/vpd-manager/manager.hpp b/vpd-manager/manager.hpp
index 41d3ad7..fd1a306 100644
--- a/vpd-manager/manager.hpp
+++ b/vpd-manager/manager.hpp
@@ -129,6 +129,16 @@
      */
     void processJSON();
 
+    /** @brief Api to register host state callback.
+     * This api will register callback to listen for host state property change.
+     */
+    void listenHostState();
+
+    /** @brief Callback to listen for Host state change
+     *  @param[in] msg - callback message.
+     */
+    void hostStateCallBack(sdbusplus::message::message& msg);
+
     /** @brief Persistent sdbusplus DBus bus connection. */
     sdbusplus::bus::bus _bus;