[gtk] textview: clear cached entries before releasing containers

[Christian Hergert <chergert src gnome org>]

commit 4ae362d1382588c1519b2e6cac1edc79294e8fb5
Author: Christian Hergert <chergert redhat com>
Date:   Fri Aug 9 12:52:16 2019 -0700

    textview: clear cached entries before releasing containers
    
    We want to ensure all of the display cache entries are released in the
    normal fashion before releasing the structures so that we can maintain
    the invariant that cache_iter will always exist while in the cache.

 gtk/gtktextlinedisplaycache.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gtk/gtktextlinedisplaycache.c b/gtk/gtktextlinedisplaycache.c
index 6129d787fc..267d9f6182 100644
--- a/gtk/gtktextlinedisplaycache.c
+++ b/gtk/gtktextlinedisplaycache.c
@@ -93,6 +93,8 @@ gtk_text_line_display_cache_free (GtkTextLineDisplayCache *cache)
   g_clear_handle_id (&cache->log_source, g_source_remove);
 #endif
 
+  gtk_text_line_display_cache_invalidate (cache);
+
   g_clear_pointer (&cache->evict_source, g_source_destroy);
   g_clear_pointer (&cache->sorted_by_line, g_sequence_free);
   g_clear_pointer (&cache->line_to_display, g_hash_table_unref);