[libdazzle] shortcuts: ignore controller if no global keybindings are registered

[Christian Hergert <chergert src gnome org>]

commit e25ca9c8511706edafa79da20e8a53b688da8817
Author: Christian Hergert <chergert redhat com>
Date:   Sun May 5 10:06:13 2019 -0700

    shortcuts: ignore controller if no global keybindings are registered
    
    This may be masking another problem, but it is a short-circuit we should
    be doing nonetheless. The themes shouldn't be able to add any global
    keybindings that don't already exist as global command/action/callbacks.

 src/shortcuts/dzl-shortcut-controller.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/shortcuts/dzl-shortcut-controller.c b/src/shortcuts/dzl-shortcut-controller.c
index 604bf8f..f079d15 100644
--- a/src/shortcuts/dzl-shortcut-controller.c
+++ b/src/shortcuts/dzl-shortcut-controller.c
@@ -857,6 +857,9 @@ dzl_shortcut_controller_do_global (DzlShortcutController  *self,
   g_assert ((phase & DZL_SHORTCUT_PHASE_GLOBAL) != 0);
   g_assert (GTK_IS_WIDGET (widget));
 
+  if (!priv->have_global)
+    return DZL_SHORTCUT_MATCH_NONE;
+
   manager = dzl_shortcut_controller_get_manager (self);
   g_assert (DZL_IS_SHORTCUT_CONTROLLER (self));