Hide UserRole from public interface

All commands added using API executed as Owner's commands.

BUG:24267885
Change-Id: I296e9503cac07d84664941278ffb56f79f695fb0
Reviewed-on: https://weave-review.googlesource.com/1225
Reviewed-by: Alex Vakulenko <avakulenko@google.com>
diff --git a/libweave/src/commands/command_definition.h b/libweave/src/commands/command_definition.h
index 06d7afd..a6a17f8 100644
--- a/libweave/src/commands/command_definition.h
+++ b/libweave/src/commands/command_definition.h
@@ -15,6 +15,13 @@
 
 namespace weave {
 
+enum class UserRole {
+  kViewer,
+  kUser,
+  kManager,
+  kOwner,
+};
+
 // A simple GCD command definition. This class contains the command category
 // and a full object schema describing the command parameter types and
 // constraints. See comments for CommandDefinitions::LoadCommands for the