Neuter the wrong-way ServiceProvider (a.k.a. exposed_services).

mojo/public/interfaces/application/shell.mojom

Index: mojo/public/interfaces/application/shell.mojom
diff --git a/mojo/public/interfaces/application/shell.mojom b/mojo/public/interfaces/application/shell.mojom
index dc210c74461f6781eacf1e2375ca7721aa68fe6b..d00ac01d9ad99324d9dd45823da32ebd2b49ac12 100644
--- a/mojo/public/interfaces/application/shell.mojom
+++ b/mojo/public/interfaces/application/shell.mojom
@@ -12,7 +12,13 @@ import "mojo/public/interfaces/application/service_provider.mojom";
 // system and request connections to other applications.
 interface Shell {
   // See |ApplicationConnector.ConnectToApplication()|.
-  // TODO(vtl): Maybe this should be deprecated/removed.
+  //
+  // WARNING: |exposed_services| is deprecated and non-functional, and will be
+  // removed. Note that this also means that |services| will become required.
+  // https://github.com/domokit/mojo/issues/762
+  //
+  // TODO(vtl): Maybe this should be deprecated/removed (in favor of just using
+  // |ApplicationConnector|).
   ConnectToApplication(string application_url,
                        ServiceProvider&? services,
                        ServiceProvider? exposed_services);