dash: simplify app retrieval from AppWellIcon

This has also the benefit of getting the application even if it can not
be retrieved through AppSystem, which can happen if the runtime WMClass
does not match the one of the desktop file.

This especially looked wrong with the following commits related to the
bug.

https://bugzilla.gnome.org/show_bug.cgi?id=657315

diff --git a/js/ui/dash.js b/js/ui/dash.js
index 21594b59c8984e44e794cf9a8a8f483634494a22..d367aaac972b4533f5702b8749dde5926309011c 100644 (file)
--- a/js/ui/dash.js
+++ b/js/ui/dash.js
@@ -23,8 +23,7 @@ const DASH_ITEM_HOVER_TIMEOUT = 300;
 
 function getAppFromSource(source) {
     if (source instanceof AppDisplay.AppWellIcon) {
-        let appSystem = Shell.AppSystem.get_default();
-        return appSystem.lookup_app(source.getId());
+        return source.app;
     } else if (source.metaWindow) {
         let tracker = Shell.WindowTracker.get_default();
         return tracker.get_window_app(source.metaWindow);