make sure we save the page_id for the page when its created so we can use it later. fix user session sometimes having value of 'null' in default theme.

src/greeter.c

@@ -177,8 +177,6 @@ theme_heartbeat_script_loaded_cb(GObject *object,
 								 gpointer user_data) {
 
 	WebKitJavascriptResult *js_result;
-	JSValueRef              value;
-	JSGlobalContextRef      context;
 	GError                 *error = NULL;
 
 	js_result = webkit_web_view_run_javascript_from_gresource_finish(

src/webkit2-extension.c

@@ -1649,6 +1649,15 @@ autologin_timer_expired_cb(LightDMGreeter *greeter, WebKitWebExtension *extensio
 }
 
 
+void
+page_created_cb(WebKitWebExtension *extension,
+				WebKitWebPage      *web_page,
+				gpointer            user_data) {
+
+	page_id = webkit_web_page_get_id(web_page);
+}
+
+
 G_MODULE_EXPORT void
 webkit_web_extension_initialize(WebKitWebExtension *extension) {
 	LightDMGreeter *greeter = lightdm_greeter_new();
@@ -1663,6 +1672,11 @@ webkit_web_extension_initialize(WebKitWebExtension *extension) {
 					 G_CALLBACK(autologin_timer_expired_cb),
 					 extension);
 
+	g_signal_connect(G_OBJECT(extension),
+					 "page-created",
+					 G_CALLBACK(page_created_cb),
+					 NULL);
+
 	g_signal_connect(webkit_script_world_get_default(),
 					 "window-object-cleared",
 					 G_CALLBACK(window_object_cleared_callback),

themes/antergos/js/greeter.js

@@ -213,6 +213,11 @@ class AntergosThemeUtils {
 		this.background_images_dir = background_images_dir;
 	}
 
+	is_not_empty( value ) {
+		empty_values = [null, 'null', undefined, 'undefined'];
+		return empty_values.findIndex(v => v === value) === -1;
+	}
+
 
 	find_images( dirlist ) {
 		var images = [],
@@ -661,7 +666,7 @@ class AntergosTheme {
 		var user_id = $( this ).attr( 'id' ),
 			selector = `.${user_id}`,
 			user_session_cached = _util.cache_get( 'user', user_id, 'session' ),
-			user_session = (null !== user_session_cached) ? user_session_cached : lightdm.default_session;
+			user_session = (_util.is_not_empty( user_session_cached )) ? user_session_cached : lightdm.default_session;
 
 		if ( _self.auth_pending || null !== _self.selected_user ) {
 			lightdm.cancel_authentication();