BMediaRoster: Reintroduce the undertaker class

* This has been necessary due to the undefined call order of
of static objects. Fixes #12315.
* The bug has been caused by the linker which free unused resources,
making the BMediaRoster to run in a zombie state. In this state
anything such as a message could make the looper to crash.
* The class is reintroduced with some differences though, we are
going to protect it from another thread calling Roster() while the
BMediaRoster is quitting and implement BMediaRosterEx::Quit.
* Unregister registrar notifications before we quit our thread. Avoid
to uninitialize anything from QuitRequested as it may cause problems.

headers/private/media/MediaRosterEx.h

@@ -37,6 +37,8 @@ public:
 							BMediaRosterEx(status_t* out_error);
 		virtual				~BMediaRosterEx();
 
+		virtual void		Quit();
+
 		status_t			SaveNodeConfiguration(BMediaNode* node);
 		status_t 			LoadNodeConfiguration(media_addon_id addonid,
 							int32 flavorid, BMessage* out_msg);

src/kits/media/MediaRoster.cpp

@@ -86,6 +86,22 @@ static bool sServerIsUp = false;
 static List<RosterNotification> sNotificationList;
 static BLocker sInitLocker("BMediaRoster::Roster locker");
 
+
+class MediaRosterUndertaker {
+public:
+	~MediaRosterUndertaker()
+	{
+		BAutolock _(sInitLocker);
+		if (BMediaRoster::CurrentRoster() != NULL
+				&& BMediaRoster::CurrentRoster()->Lock()) {
+			BMediaRoster::CurrentRoster()->Quit();
+		}
+	}
+};
+
+
+static MediaRosterUndertaker sMediaRosterUndertaker;
+
 }	// namespace media
 }	// namespace BPrivate
 
@@ -96,8 +112,8 @@ BMediaRosterEx::BMediaRosterEx(status_t* _error)
 	:
 	BMediaRoster()
 {
-	gDormantNodeManager = new DormantNodeManager;
+	gDormantNodeManager = new DormantNodeManager();
-	gTimeSourceObjectManager = new TimeSourceObjectManager;
+	gTimeSourceObjectManager = new TimeSourceObjectManager();
 
 	*_error = BuildConnections();
 
@@ -111,6 +127,19 @@ BMediaRosterEx::BMediaRosterEx(status_t* _error)
 }
 
 
+void
+BMediaRosterEx::Quit()
+{
+	if (be_roster->StopWatching(BMessenger(this, this)) != B_OK)
+			TRACE("Can't unregister roster notifications");
+
+	if (sNotificationList.CountItems() != 0)
+		sNotificationList.MakeEmpty();
+
+	BMediaRoster::Quit();
+}
+
+
 status_t
 BMediaRosterEx::BuildConnections()
 {
@@ -3474,13 +3503,6 @@ bool
 BMediaRoster::QuitRequested()
 {
 	CALLED();
-
-	if (be_roster->StopWatching(BMessenger(this, this)) != B_OK)
-			TRACE("Can't unregister roster notifications");
-
-	if (sNotificationList.CountItems() != 0)
-		sNotificationList.MakeEmpty();
-
 	return true;
 }