Create the port pool in MediaRosterUndertaker

Follow up to #15135, which created a regression, apps would crash if
using the port pool before creating a BMediaRoster instance. Now the
port pool is entirely managed by the MediaRosterUndertaker, which is
less confusing.

Fixes the media_addon_server crash on shutdown for me as well, but I
don't remember why (I had studied the code and came to the conclusion
that this should fix it, but I don't remember the reasoning).

Fixes #15263, and regressions for apps using the port pool before they
instanciate the BMediaRoster.

Change-Id: I887dbc590d8ee9de391b6eae0206944bfe99325f
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1897
Reviewed-by: Axel Dörfler <[email protected]>

src/kits/media/MediaRoster.cpp

@@ -115,8 +115,17 @@ static BLocker sInitLocker("BMediaRoster::Roster locker");
 static List<LocalNode> sRegisteredNodes;
 
 
+// This class takes care of all static initialization and destruction of
+// libmedia objects. It guarantees that things are created and destroyed in
+// the correct order, as well as performing some "garbage collecting" by being
+// destructed automatically on application exit.
 class MediaRosterUndertaker {
 public:
+	MediaRosterUndertaker()
+	{
+		gPortPool = new PortPool();
+	}
+
 	~MediaRosterUndertaker()
 	{
 		BAutolock _(sInitLocker);
@@ -169,9 +178,6 @@ BMediaRosterEx::BMediaRosterEx(status_t* _error)
 {
 	gDormantNodeManager = new DormantNodeManager();
 	gTimeSourceObjectManager = new TimeSourceObjectManager();
-	gPortPool = new PortPool();
-		// This is created here but deleted in the MediaRosterUndertaker because
-		// otherwise there are segfaults trying to send final quit messages.
 
 	*_error = BuildConnections();
 

src/kits/media/PortPool.cpp

@@ -19,7 +19,7 @@ namespace media {
 
 
 PortPool* gPortPool;
-	// initialized by BMediaRosterEx, deleted by MediaRosterUndertaker.
+	// managed by MediaRosterUndertaker.
 
 
 PortPool::PortPool()