Wait until the desktop ends starting up

Gnome Shell enables the extensions before the desktop itself is
ready to accept widgets. This can result in errors. In the case
of appindicator, it results in applications that are launched
during startup will not show an indicator because, when the
extension tries to add the icon to the Gnome Shell interface,
it isn't ready for that, thus failing. But other applications,
launched after the Shell has completed the startup process,
will work fine.

This patch fixes this by checking in the `enable()` method if
Gnome Shell is still starting up, in which case it waits until
the `startup-complete` signal is triggered before continuing.

extension.js

@@ -15,6 +15,7 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 const Gio = imports.gi.Gio
 const GLib = imports.gi.GLib
+const Main = imports.ui.main;
 
 const Extension = imports.misc.extensionUtils.getCurrentExtension()
 
@@ -24,6 +25,7 @@ const Util = Extension.imports.util
 let statusNotifierWatcher = null;
 let isEnabled = false;
 let watchDog = null;
+let startupPreparedId;
 
 function init() {
  watchDog = new NameWatchdog();
@@ -51,11 +53,21 @@ function maybe_enable_after_name_available() {
  statusNotifierWatcher = new StatusNotifierWatcher.StatusNotifierWatcher(watchDog);
 }
 
-function enable() {
+function inner_enable(disconnect_startup_complete) {
+ if (disconnect_startup_complete)
+ Main.layoutManager.disconnect(startupPreparedId);
  isEnabled = true;
  maybe_enable_after_name_available();
 }
 
+function enable() {
+ // If the desktop is still starting up, we wait until it is ready
+ if (Main.layoutManager._startingUp)
+ startupPreparedId = Main.layoutManager.connect('startup-complete', () => { inner_enable(true); });
+ else
+ inner_enable(false);
+}
+
 function disable() {
  isEnabled = false;
  if (statusNotifierWatcher !== null) {