Add a "toggle_recording" keybinding

Add a keybinding (defaulting to <Control><Shift><Alt>r) to record
a screencast of the session. This isn't hooked up to anything in
metacity itself, but a plugin can connect to a signal on MetaScreen.

keybindings.c all-keybindings.h: Add the keybinding
screen.c: Add a ::toggle-recording signal

http://bugzilla.gnome.org/show_bug.cgi?id=575290

src/core/keybindings.c

@@ -2853,6 +2853,17 @@ handle_panel (MetaDisplay    *display,
   meta_error_trap_pop (display, FALSE);
 }
 
+static void
+handle_toggle_recording (MetaDisplay    *display,
+                         MetaScreen     *screen,
+                         MetaWindow     *window,
+                         XEvent         *event,
+                         MetaKeyBinding *binding,
+                         gpointer        dummy)
+{
+  g_signal_emit_by_name (screen, "toggle-recording");
+}
+
 static void
 handle_activate_window_menu (MetaDisplay    *display,
                       MetaScreen     *screen,

src/core/screen.c

@@ -77,6 +77,7 @@ enum
 enum
 {
   RESTACKED,
+  TOGGLE_RECORDING,
 
   LAST_SIGNAL
 };
@@ -153,6 +154,15 @@ meta_screen_class_init (MetaScreenClass *klass)
                             1, G_MAXINT, 1,
                             G_PARAM_READABLE);
 
+  screen_signals[TOGGLE_RECORDING] =
+    g_signal_new ("toggle-recording",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL,
+                  g_cclosure_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
+
   g_object_class_install_property (object_class,
                                    PROP_N_WORKSPACES,
                                    pspec);

src/include/all-keybindings.h

@@ -195,6 +195,8 @@ keybind (panel_main_menu, handle_panel,
 keybind (panel_run_dialog, handle_panel,
        META_KEYBINDING_ACTION_PANEL_RUN_DIALOG, 0, "<Alt>F2",
       _("Show the panel's \"Run Application\" dialog box"))
+keybind (toggle_recording, handle_toggle_recording, 0, 0, "<Control><Shift><Alt>r",
+         _("Start or stop recording the session"))
 
 /* Yes, the param is offset by one.  Historical reasons.  (Maybe worth fixing
  * at some point.)  The description is NULL here because the stanza is