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

mojo/public/interfaces/bindings/tests/versioning_test_service.mojom

 // Copyright 2015 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.versioning;
 
 // versioning_test_service.mojom and versioning_test_client.mojom contain
 // different versions of Mojom definitions for a fictitious human resource
 // management system. They are used to test the versioning mechanism.
 
 enum Department {
   SALES,
   DEV
 };
 
 struct Date {
   uint16 year;
   uint8 month;
   uint8 day;
 };
 
 struct Employee {
   uint64 employee_id;
   string name;
   Department department;
   [MinVersion=1] Date? birthday;
 };
 
+[ServiceName="mojo::test::versioning::HumanResourceDatabase"]
 interface HumanResourceDatabase {
   AddEmployee(Employee employee) => (bool success);
 
   QueryEmployee(uint64 id, [MinVersion=1] bool retrieve_finger_print)
       => (Employee? employee, [MinVersion=1] array<uint8>? finger_print);
 
   [MinVersion=1]
   AttachFingerPrint(uint64 id, array<uint8> finger_print)
       => (bool success);
 };