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

mojo/services/nfc/interfaces/nfc.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.
 
 [DartPackage="mojo_services"]
 module nfc;
 
 struct NfcData {
   array<uint8>? data;
 };
 
 // Represents an in-progress nfc transmission.
 interface NfcTransmission {
   // Cancels the nfc transmission.
   Cancel();
 };
 
 // NfcReceivers can be registered with Nfc to receive nfc messages.
+[ServiceName="nfc::NfcReceiver"]
 interface NfcReceiver {
   OnReceivedNfcData(NfcData nfc_data);
 };
 
 // Nfc allows data to be sent to and received from other MojoShells on Android.
 // Received data is passed to all registered NfcReceivers.
+[ServiceName="nfc::Nfc"]
 interface Nfc {
   // Puts the MojoShell in a state where it will transmit |nfc_data| to the next
   // Android device to connect to this one via NFC.  This transmission state
   // will remain active until cancelled via |transmission| or a |success|
   // response is received indicating whether the transmission was successful
   // (true) or not (false).  If the Android device transmitted to does not have
   // MojoShell installed it will be directed to the Play Store to download
   // MojoShell.
   TransmitOnNextConnection(NfcData nfc_data, NfcTransmission&? transmission)
     => (bool success);
 
   // Registers an app to receive nfc messages.  Upon receiving an nfc message
   // the app will be connected to.  If the app exposes a NfcReceiver interface
   // it will be called with the message received.
   Register();
 
   // Unregisters an app previously registered via |Register()|.
   Unregister();
 };