Make realm a non-drawable component to better order disposal

Until now, the `RealmContextFactory` would be disposed as part of the
drawable hierarchy. This is too early, as it may be being used by higher
level components (like `ConfigManager`s, see #15115) that perform final
operations after the drawables have been disposed.

Seems to make sense moving this out of the drawable hierarchy and in
line with how we were doing things with EF.

osu.Game/Database/RealmContextFactory.cs

@@ -5,7 +5,6 @@ using System;
 using System.Threading;
 using osu.Framework.Allocation;
 using osu.Framework.Development;
-using osu.Framework.Graphics;
 using osu.Framework.Logging;
 using osu.Framework.Platform;
 using osu.Framework.Statistics;
@@ -18,7 +17,7 @@ namespace osu.Game.Database
     /// <summary>
     /// A factory which provides both the main (update thread bound) realm context and creates contexts for async usage.
     /// </summary>
-    public class RealmContextFactory : Component, IRealmFactory
+    public class RealmContextFactory : IDisposable, IRealmFactory
     {
         private readonly Storage storage;
 
@@ -79,10 +78,11 @@ namespace osu.Game.Database
         /// <returns></returns>
         public bool Compact() => Realm.Compact(getConfiguration());
 
-        protected override void Update()
+        /// <summary>
+        /// Perform a blocking refresh on the main realm context.
+        /// </summary>
+        public void Refresh()
         {
-            base.Update();
-
             lock (contextLock)
             {
                 if (context?.Refresh() == true)
@@ -92,7 +92,7 @@ namespace osu.Game.Database
 
         public Realm CreateContext()
         {
-            if (IsDisposed)
+            if (isDisposed)
                 throw new ObjectDisposedException(nameof(RealmContextFactory));
 
             try
@@ -132,7 +132,7 @@ namespace osu.Game.Database
         /// <returns>An <see cref="IDisposable"/> which should be disposed to end the blocking section.</returns>
         public IDisposable BlockAllOperations()
         {
-            if (IsDisposed)
+            if (isDisposed)
                 throw new ObjectDisposedException(nameof(RealmContextFactory));
 
             if (!ThreadSafety.IsUpdateThread)
@@ -176,21 +176,23 @@ namespace osu.Game.Database
             });
         }
 
-        protected override void Dispose(bool isDisposing)
+        private bool isDisposed;
+
+        public void Dispose()
         {
             lock (contextLock)
             {
                 context?.Dispose();
             }
 
-            if (!IsDisposed)
+            if (!isDisposed)
             {
                 // intentionally block context creation indefinitely. this ensures that nothing can start consuming a new context after disposal.
                 contextCreationLock.Wait();
                 contextCreationLock.Dispose();
-            }
 
-            base.Dispose(isDisposing);
+                isDisposed = true;
+            }
         }
     }
 }

osu.Game/OsuGameBase.cs

@@ -187,8 +187,6 @@ namespace osu.Game
 
             dependencies.Cache(realmFactory = new RealmContextFactory(Storage, "client"));
 
-            AddInternal(realmFactory);
-
             dependencies.CacheAs(Storage);
 
             var largeStore = new LargeTextureStore(Host.CreateTextureLoaderStore(new NamespacedResourceStore<byte[]>(Resources, @"Textures")));
@@ -529,6 +527,7 @@ namespace osu.Game
             LocalConfig?.Dispose();
 
             contextFactory?.FlushConnections();
+            realmFactory?.Dispose();
         }
     }
 }