Mojom: Blanket change to mark all pointer/handle fields as nullable.

mojo/public/interfaces/application/service_provider.mojom

Index: mojo/public/interfaces/application/service_provider.mojom
diff --git a/mojo/public/interfaces/application/service_provider.mojom b/mojo/public/interfaces/application/service_provider.mojom
index 1d006b43a0fb5222a6363ec46fbbf683f9b514dd..00eb057c9f32fbd012c1119b0a087d3879c75be4 100644
--- a/mojo/public/interfaces/application/service_provider.mojom
+++ b/mojo/public/interfaces/application/service_provider.mojom
@@ -10,7 +10,7 @@ module mojo {
 interface ServiceProvider {
   // Connect the given message pipe handle to the named service. If the named
   // service does not exist, then the handle will be closed.
-  ConnectToService(string interface_name, handle<message_pipe> pipe);
+  ConnectToService(string? interface_name, handle<message_pipe>? pipe);
 };
 
 }