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

mojo/services/network/interfaces/network_service.mojom

Index: mojo/services/network/interfaces/network_service.mojom
diff --git a/mojo/services/network/interfaces/network_service.mojom b/mojo/services/network/interfaces/network_service.mojom
index c1f957cc376ef070684098cd4bcdba06fffd48c1..8ab0d1a4f7d14e6d8626f202fd1696f83f69c476 100644
--- a/mojo/services/network/interfaces/network_service.mojom
+++ b/mojo/services/network/interfaces/network_service.mojom
@@ -20,6 +20,7 @@ import "network/interfaces/web_socket.mojom";
 // TODO Darin suggests that this should probably be two classes. One for
 // high-level origin-build requests like WebSockets and HTTP, and the other for
 // non-origin-bound low-level stuff like DNS, UDP, and TCP.
+[ServiceName="mojo::NetworkService"]
 interface NetworkService {
   CreateURLLoader(URLLoader& loader);