shell/window-tracker: Exclude screen recorder window

The pipeline contains a GST plugin that pops up an unclosable
zero-sized window.

Unfortunately we did not manage to come up with a proper fix
in time, so for now explicitly exclude it from app tracking.

This does not address all issues (it still prevents the
window's workspace from getting removed, even when it appears
empty), but at least it avoids the most confusing effect by
preventing the "app" from showing up in dash, alt-tab etc.

https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/6763

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2956>

src/shell-window-tracker.c

@@ -412,6 +412,13 @@ get_app_for_window (ShellWindowTracker    *tracker,
   if (meta_window_is_remote (window))
     return _shell_app_new_for_window (window);
 
+  /* HACK: Exclude screen recorder from tracking until
+   * we implement a proper fix
+   */
+  if (meta_window_get_wm_class (window) == NULL &&
+      g_strcmp0 (meta_window_get_title (window), "OpenGL Renderer") == 0)
+    return NULL;
+
   /* Check if the app's WM_CLASS specifies an app; this is
    * canonical if it does.
    */