mf: Make freeing function optional for object activator.

dlls/mf/evr.c

@@ -258,15 +258,10 @@ static void evr_shutdown_object(void *user_context, IUnknown *obj)
     }
 }
 
-static void evr_free_private(void *user_context)
-{
-}
-
 static const struct activate_funcs evr_activate_funcs =
 {
-    evr_create_object,
-    evr_shutdown_object,
-    evr_free_private,
+    .create_object = evr_create_object,
+    .shutdown_object = evr_shutdown_object,
 };
 
 /***********************************************************************

dlls/mf/main.c

@@ -91,7 +91,8 @@ static ULONG WINAPI activate_object_Release(IMFActivate *iface)
 
     if (!refcount)
     {
-        activate->funcs->free_private(activate->context);
+        if (activate->funcs->free_private)
+            activate->funcs->free_private(activate->context);
         if (activate->object)
             IUnknown_Release(activate->object);
         IMFAttributes_Release(activate->attributes);

dlls/mf/sar.c

@@ -1891,15 +1891,10 @@ static void sar_shutdown_object(void *user_context, IUnknown *obj)
     }
 }
 
-static void sar_free_private(void *user_context)
-{
-}
-
 static const struct activate_funcs sar_activate_funcs =
 {
-    sar_create_object,
-    sar_shutdown_object,
-    sar_free_private,
+    .create_object = sar_create_object,
+    .shutdown_object = sar_shutdown_object,
 };
 
 /***********************************************************************