[session] Initialize ViewSpec to empty() for default fields

Change-Id: I40b409cfe35c52315f8673ed261f421f171a5874
Reviewed-on: https://fuchsia-review.googlesource.com/c/experiences/+/410805
Commit-Queue: Sanjay Chouksey <sanjayc@google.com>
Reviewed-by: Chase Latta <chaselatta@google.com>
Testability-Review: Chase Latta <chaselatta@google.com>
diff --git a/session_shells/ermine/session/src/element_repository/event_handler.rs b/session_shells/ermine/session/src/element_repository/event_handler.rs
index 20df0b2..fa3b88a 100644
--- a/session_shells/ermine/session/src/element_repository/event_handler.rs
+++ b/session_shells/ermine/session/src/element_repository/event_handler.rs
@@ -63,6 +63,7 @@
         let view_spec = ViewSpec {
             view_holder_token: Some(token_pair.view_holder_token),
             annotations: Some(annotations),
+            ..ViewSpec::empty()
         };
 
         let (view_controller_proxy, server_end) = create_proxy::<ViewControllerMarker>()?;