introspect: Fix whitelist check

The whitelist is a list of well-known D-Bus names, which we then search
for the unique name we get from the method invocation - unsuccesfully.

Fix this by watching the bus for any name in the whitelist in order
to maintain a map from wel-known to unique name that we can use for
matching.

https://gitlab.gnome.org/GNOME/gnome-shell/issues/1916


(cherry picked from commit eee1ab4890)

js/misc/introspect.js

@@ -40,6 +40,15 @@ var IntrospectService = class {
                         });
 
         this._syncRunningApplications();
+
+        this._whitelistMap = new Map();
+        APP_WHITELIST.forEach(appName => {
+            Gio.DBus.watch_name(Gio.BusType.SESSION,
+                appName,
+                Gio.BusNameWatcherFlags.NONE,
+                (conn, name, owner) => this._whitelistMap.set(name, owner),
+                (conn, name) => this._whitelistMap.delete(name));
+        });
     }
 
     _isStandaloneApp(app) {
@@ -51,7 +60,7 @@ var IntrospectService = class {
     }
 
     _isSenderWhitelisted(sender) {
-        return APP_WHITELIST.includes(sender);
+        return [...this._whitelistMap.values()].includes(sender);
     }
 
     _getSandboxedAppId(app) {