shellDBus: Fix FocusApp()

The appDisplay used to be accessible via the viewSelector, but
that is gone now. Commit c09c070b15 adjusted the code, but the
replacement uses a Main.overview.appDisplay accessor that never
existed, whoops.

Fix this by exposing a new selectApp() method directly on the
overview, so we don't have to shuffle the appDisplay through
controls → overviewActor → overview.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1891>

js/ui/overview.js

@@ -642,6 +642,11 @@ var Overview = class {
         this.show(OverviewControls.ControlsState.APP_GRID);
     }
 
+    selectApp(id) {
+        this.showApps();
+        this._overview.controls.appDisplay.selectApp(id);
+    }
+
     runStartupAnimation(callback) {
         Main.panel.style = 'transition-duration: 0ms;';
 

js/ui/shellDBus.js

@@ -100,8 +100,7 @@ var GnomeShell = class {
     }
 
     FocusApp(id) {
-        this.ShowApplications();
+        Main.overview.selectApp(id);
-        Main.overview.appDisplay.selectApp(id);
     }
 
     ShowApplications() {