RosterPrivate: add IsShutDownInProgress()

enable to check whether a shutdown process is in progress.

Change-Id: I8efdddb3caa80e9fd188f202b6e92a888a7608e5
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2042
Reviewed-by: waddlesplash <[email protected]>

headers/os/app/Roster.h

@@ -147,6 +147,7 @@ private:
 
 			status_t			_ShutDown(bool reboot, bool confirm,
 									bool synchronous);
+			status_t			_IsShutDownInProgress(bool* inProgress);
 
 			status_t			_AddApplication(const char* signature,
 									const entry_ref* ref, uint32 flags,

headers/private/app/RegistrarDefs.h

@@ -46,6 +46,7 @@ enum {
 	B_REG_GET_CLIPBOARD_MESSENGER			= 'rgcm',
 	B_REG_GET_DISK_DEVICE_MESSENGER			= 'rgdm',
 	B_REG_SHUT_DOWN							= 'rgsh',
+	B_REG_IS_SHUT_DOWN_IN_PROGRESS			= 'rgsi',
 
 	// roster requests
 	B_REG_ADD_APP							= 'rgaa',

headers/private/app/RosterPrivate.h

@@ -39,6 +39,8 @@ class BRoster::Private {
 
 		status_t ShutDown(bool reboot, bool confirm, bool synchronous)
 			{ return fRoster->_ShutDown(reboot, confirm, synchronous); }
+		status_t IsShutDownInProgress(bool* inProgress)
+			{ return fRoster->_IsShutDownInProgress(inProgress); }
 
 		// needed by BApplication