Require an explicit ServiceName annotation for interfaces in C++.

mojo/services/window_manager/interfaces/window_manager.mojom

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [DartPackage="mojo_services"]
 module mojo;
 
 import "input_events/interfaces/input_events.mojom";
 import "mojo/public/interfaces/application/service_provider.mojom";
 
+[ServiceName="mojo::WindowManager"]
 interface WindowManager {
   // Requests the WindowManager to embed the app for |url| at an appropriate
   // View. See ViewMangerService::Embed() for details on |services| and
   // |exposed_services|.
   Embed(string url,
         ServiceProvider&? services,
         ServiceProvider? exposed_services);
 
   SetCapture(uint32 view_id) => (bool success);
   FocusWindow(uint32 view_id) => (bool success);
   ActivateWindow(uint32 view_id) => (bool success);
 
   // Requests the current focus and activation state and an interface to observe
   // future changes.
   // If |observer| is not null capture, focus and activation updates will be
   // sent to it.
   GetFocusedAndActiveViews(WindowManagerObserver? observer)
       => (uint32 capture_view_id,
           uint32 focused_view_id,
           uint32 active_view_id);
 };
 
 interface WindowManagerObserver {
   OnCaptureChanged(uint32 capture_view_id);
   OnFocusChanged(uint32 focused_view_id);
   OnActiveWindowChanged(uint32 focused_view_id);
 };