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

mojo/services/nfc/interfaces/nfc.mojom

Index: mojo/services/nfc/interfaces/nfc.mojom
diff --git a/mojo/services/nfc/interfaces/nfc.mojom b/mojo/services/nfc/interfaces/nfc.mojom
index c91c15bbb197c22d2419305f6aa8a62bbcc7a4c6..97bab7a7b073fa02786aa95547aa90969b3f8fce 100644
--- a/mojo/services/nfc/interfaces/nfc.mojom
+++ b/mojo/services/nfc/interfaces/nfc.mojom
@@ -16,12 +16,14 @@ interface NfcTransmission {
 };
 
 // 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