apps-menu: 'Touch' copied .desktop file after updating attributes

At least for now, nautilus' file monitor is blind to certain metadata
updates:
https://git.gnome.org/browse/nautilus/tree/src/nautilus-mime-actions.c#n1537

So in order for the changes in the previous patch to take effect
immediately, we need to force nautilus to reload the file info.
Achieve this by updating the access time of the newly copied file
after marking it as trusted.

https://bugzilla.gnome.org/show_bug.cgi?id=781596

extensions/apps-menu/extension.js

@@ -331,6 +331,23 @@ const DesktopTarget = new Lang.Class({
         return source._app.app_info;
     },
 
+    _touchFile: function(file) {
+        let queryFlags = Gio.FileQueryInfoFlags.NONE;
+        let ioPriority = GLib.PRIORITY_DEFAULT;
+
+        let info = new Gio.FileInfo();
+        info.set_attribute_uint64(Gio.FILE_ATTRIBUTE_TIME_ACCESS,
+                                  GLib.get_real_time());
+        file.set_attributes_async (info, queryFlags, ioPriority, null,
+            (o, res) => {
+                try {
+                    o.set_attributes_finish(res);
+                } catch(e) {
+                    log('Failed to update access time: ' + e.message);
+                }
+            });
+    },
+
     _markTrusted: function(file) {
         let modeAttr = Gio.FILE_ATTRIBUTE_UNIX_MODE;
         let trustedAttr = 'metadata::trusted';
@@ -348,6 +365,9 @@ const DesktopTarget = new Lang.Class({
                     file.set_attributes_async (info, queryFlags, ioPriority, null,
                         (o, res) => {
                             o.set_attributes_finish(res);
+
+                            // Hack: force nautilus to reload file info
+                            this._touchFile(file);
                         });
                 } catch(e) {
                     log('Failed to mark file as trusted: ' + e.message);