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

services/test_service/test_request_tracker.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.
 
 module mojo.test;
 
 // Various counters that services can periodically send to a
 // TestTrackedRequestService for recording.
 struct ServiceStats {
   uint64 num_new_requests;
   double health;
 };
 
 // A per-service summary of all the ServiceStats the
 // TestTrackedRequestService has observed.
 struct ServiceReport {
   string? service_name;
   uint64 total_requests;
   double mean_health;
 };
 
 // A simple interface to obtain a "report" from all services that have
 // opted to connect themselves to for request tracking.
+[ServiceName="mojo::test::TestTrackedRequestService"]
 interface TestTrackedRequestService {
   GetReport() => (array<ServiceReport?>? report);
 };
 
 // TestRequestTracker records ServiceStats for an individual service
 // connection for aggregation in a TestTrackedRequestService.
+[ServiceName="mojo::test::TestRequestTracker"]
 interface TestRequestTracker {
   SetNameAndReturnId(string service_name) => (uint64 id);
   // Upload a ServiceStats for tracking.
   RecordStats(uint64 client_id, ServiceStats? stats);
 };