Fixed #1299: New callback to notify that sound device needs to be opened or closed

git-svn-id: https://svn.pjsip.org/repos/pjproject/branches/projects/2.0-dev@3632 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/pjsip/include/pjsua-lib/pjsua_internal.h b/pjsip/include/pjsua-lib/pjsua_internal.h
index e863524..84b6b1f 100644
--- a/pjsip/include/pjsua-lib/pjsua_internal.h
+++ b/pjsip/include/pjsua-lib/pjsua_internal.h
@@ -400,7 +400,7 @@
     pj_timer_entry	 snd_idle_timer;/**< Sound device idle timer.	*/
     pjmedia_master_port	*null_snd;  /**< Master port for null sound.	*/
     pjmedia_port	*null_port; /**< Null port.			*/
-
+    pj_bool_t		 snd_is_on; /**< Media flow is currently active */
 
     /* Video device */
     pjmedia_vid_dev_index vcap_dev;  /**< Capture device ID.		*/