windowManager: Implement keybinding_filter hook

We are currently using a hack to allow a select set of keybindings
in the overview. Implement the new MetaPlugin keybinding_filter
hook, which provides a cleaner way to achieve the same.

https://bugzilla.gnome.org/show_bug.cgi?id=688202

src/gnome-shell-plugin.c

@@ -72,6 +72,9 @@ static void gnome_shell_plugin_kill_switch_workspace (MetaPlugin      *plugin);
 
 static gboolean              gnome_shell_plugin_xevent_filter (MetaPlugin *plugin,
                                                                XEvent     *event);
+
+static gboolean              gnome_shell_plugin_keybinding_filter (MetaPlugin *plugin,
+                                                                   MetaKeyBinding *binding);
 static const MetaPluginInfo *gnome_shell_plugin_plugin_info   (MetaPlugin *plugin);
 
 
@@ -126,8 +129,9 @@ gnome_shell_plugin_class_init (GnomeShellPluginClass *klass)
   plugin_class->kill_window_effects   = gnome_shell_plugin_kill_window_effects;
   plugin_class->kill_switch_workspace = gnome_shell_plugin_kill_switch_workspace;
 
-  plugin_class->xevent_filter    = gnome_shell_plugin_xevent_filter;
-  plugin_class->plugin_info      = gnome_shell_plugin_plugin_info;
+  plugin_class->xevent_filter     = gnome_shell_plugin_xevent_filter;
+  plugin_class->keybinding_filter = gnome_shell_plugin_keybinding_filter;
+  plugin_class->plugin_info       = gnome_shell_plugin_plugin_info;
 }
 
 static void
@@ -337,6 +341,13 @@ gnome_shell_plugin_xevent_filter (MetaPlugin *plugin,
   return clutter_x11_handle_event (xev) != CLUTTER_X11_FILTER_CONTINUE;
 }
 
+static gboolean
+gnome_shell_plugin_keybinding_filter (MetaPlugin     *plugin,
+                                      MetaKeyBinding *binding)
+{
+  return _shell_wm_filter_keybinding (get_shell_wm (), binding);
+}
+
 static const
 MetaPluginInfo *gnome_shell_plugin_plugin_info (MetaPlugin *plugin)
 {

src/shell-wm-private.h

@@ -35,6 +35,9 @@ void _shell_wm_kill_window_effects   (ShellWM             *wm,
                                       MetaWindowActor     *actor);
 void _shell_wm_kill_switch_workspace (ShellWM             *wm);
 
+gboolean _shell_wm_filter_keybinding (ShellWM             *wm,
+                                      MetaKeyBinding      *binding);
+
 G_END_DECLS
 
 #endif /* __SHELL_WM_PRIVATE_H__ */

src/shell-wm.c

@@ -26,6 +26,7 @@ enum
   SWITCH_WORKSPACE,
   KILL_SWITCH_WORKSPACE,
   KILL_WINDOW_EFFECTS,
+  FILTER_KEYBINDING,
 
   LAST_SIGNAL
 };
@@ -115,6 +116,14 @@ shell_wm_class_init (ShellWMClass *klass)
           NULL, NULL, NULL,
 		  G_TYPE_NONE, 1,
 		  META_TYPE_WINDOW_ACTOR);
+  shell_wm_signals[FILTER_KEYBINDING] =
+    g_signal_new ("filter-keybinding",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  g_signal_accumulator_true_handled, NULL, NULL,
+                  G_TYPE_BOOLEAN, 1,
+                  META_TYPE_KEY_BINDING);
 }
 
 void
@@ -267,6 +276,17 @@ _shell_wm_destroy (ShellWM         *wm,
   g_signal_emit (wm, shell_wm_signals[DESTROY], 0, actor);
 }
 
+gboolean
+_shell_wm_filter_keybinding (ShellWM             *wm,
+                             MetaKeyBinding      *binding)
+{
+  gboolean rv;
+
+  g_signal_emit (wm, shell_wm_signals[FILTER_KEYBINDING], 0, binding, &rv);
+
+  return rv;
+}
+
 /**
  * shell_wm_new:
  * @plugin: the #MetaPlugin