compositor: fix possible crash closing/destroying window

Partially restore call to destroy_win in compositor when calling
meta_window_free. This is needed to ensure that we never call
meta_window_get_frame_bounds while windows is destroying.

https://bugzilla.gnome.org/show_bug.cgi?id=751833

upstream commit:
https://gitlab.gnome.org/GNOME/metacity/commit/a9f28dbc

3 files changed, 32 insertions, 9 deletions

diff --git a/src/compositor/compositor-private.h b/src/compositor/compositor-private.h
index fcb15187..1fa64695 100644
--- a/src/compositor/compositor-private.h
+++ b/src/compositor/compositor-private.h
@@ -50,6 +50,9 @@ struct _MetaCompositor
                              MetaScreen     *screen,
                              MetaWindow     *window);
 
+  void (*free_window) (MetaCompositor *compositor,
+                       MetaWindow     *window);
+
   void (*maximize_window)   (MetaCompositor *compositor,
                              MetaWindow     *window);
   void (*unmaximize_window) (MetaCompositor *compositor,
diff --git a/src/compositor/compositor-xrender.c b/src/compositor/compositor-xrender.c
index dc7ac15f..abcf51ae 100644
--- a/src/compositor/compositor-xrender.c
+++ b/src/compositor/compositor-xrender.c
@@ -3040,23 +3040,38 @@ xrender_end_move (MetaCompositor *compositor,
 #ifdef HAVE_COMPOSITE_EXTENSIONS
 #endif
 }
+#endif /* 0 */
 
 static void
 xrender_free_window (MetaCompositor *compositor,
                      MetaWindow     *window)
 {
 #ifdef HAVE_COMPOSITE_EXTENSIONS
-  /* FIXME: When an undecorated window is hidden this is called,
-     but the window does not get readded if it is subsequentally shown again
-     See http://bugzilla.gnome.org/show_bug.cgi?id=504876
-
-     I don't *think* theres any need for this call anyway, leaving it out
-     does not seem to cause any side effects so far, but I should check with
-     someone who understands more. */
-  /* destroy_win (compositor->display, window->xwindow, FALSE); */
+  MetaCompositorXRender *xrc;
+  MetaFrame *frame;
+  Window xwindow;
+
+  xrc = (MetaCompositorXRender *) compositor;
+  frame = meta_window_get_frame (window);
+  xwindow = None;
+
+  if (frame)
+    {
+      xwindow = meta_frame_get_xwindow (frame);
+    }
+  else
+    {
+      /* FIXME: When an undecorated window is hidden this is called, but the
+       * window does not get readded if it is subsequentally shown again. See:
+       * http://bugzilla.gnome.org/show_bug.cgi?id=504876
+       */
+      /* xwindow = meta_window_get_xwindow (window); */
+    }
+
+  if (xwindow != None)
+    destroy_win (xrc->display, xwindow, FALSE);
 #endif
 }
-#endif /* 0 */
 
 static void
 xrender_process_event (MetaCompositor *compositor,
@@ -3360,6 +3375,7 @@ static MetaCompositor comp_info = {
   xrender_process_event,
   xrender_get_window_surface,
   xrender_set_active_window,
+  xrender_free_window,
   xrender_maximize_window,
   xrender_unmaximize_window,
 };
diff --git a/src/compositor/compositor.c b/src/compositor/compositor.c
index 7e3c79c2..39344e82 100644
--- a/src/compositor/compositor.c
+++ b/src/compositor/compositor.c
@@ -156,6 +156,10 @@ void meta_compositor_end_move (MetaCompositor *compositor,
 void meta_compositor_free_window (MetaCompositor *compositor,
                                   MetaWindow     *window)
 {
+#ifdef HAVE_COMPOSITE_EXTENSIONS
+  if (compositor && compositor->free_window)
+    compositor->free_window (compositor, window);
+#endif
 }
 
 void