[libdazzle] shortcuts: be defensive about NULL chain

[Christian Hergert <chergert src gnome org>]

commit 1f8b414331c2d139d0cd80e3d2db3faba4b98d66
Author: Christian Hergert <chergert redhat com>
Date:   Wed Aug 23 17:34:16 2017 -0700

    shortcuts: be defensive about NULL chain
    
    If we fail to parse detailed_action_name, we could get NULL back.

 src/shortcuts/dzl-shortcut-theme.c |   16 ++++++++++------
 1 files changed, 10 insertions(+), 6 deletions(-)
---
diff --git a/src/shortcuts/dzl-shortcut-theme.c b/src/shortcuts/dzl-shortcut-theme.c
index 07e53ce..f32ac0b 100644
--- a/src/shortcuts/dzl-shortcut-theme.c
+++ b/src/shortcuts/dzl-shortcut-theme.c
@@ -476,13 +476,17 @@ dzl_shortcut_theme_set_chord_for_action (DzlShortcutTheme       *self,
     phase = DZL_SHORTCUT_PHASE_BUBBLE | DZL_SHORTCUT_PHASE_GLOBAL;
 
   if (!g_hash_table_contains (priv->chains, detailed_action_name))
-  {
-    DzlShortcutClosureChain *chain;
+    {
+      DzlShortcutClosureChain *chain;
+
+      chain = dzl_shortcut_closure_chain_append_action_string (NULL, detailed_action_name);
 
-    chain = dzl_shortcut_closure_chain_append_action_string (NULL, detailed_action_name);
-    chain->phase = phase;
-    g_hash_table_insert (priv->chains, (gchar *)detailed_action_name, chain);
-  }
+      if (chain != NULL)
+        {
+          chain->phase = phase;
+          g_hash_table_insert (priv->chains, (gchar *)detailed_action_name, chain);
+        }
+    }
 }
 
 const DzlShortcutChord *