UserEvent proto exploration for Translate use case.

components/sync/protocol/proto_enum_conversions.h

Index: components/sync/protocol/proto_enum_conversions.h
diff --git a/components/sync/protocol/proto_enum_conversions.h b/components/sync/protocol/proto_enum_conversions.h
index 3cdf50dbf2783a5e3c389dfb97c16cf87c8201c2..2ec92603aa773e0b53d12eb9613c5cbff06450a9 100644
--- a/components/sync/protocol/proto_enum_conversions.h
+++ b/components/sync/protocol/proto_enum_conversions.h
@@ -81,6 +81,9 @@ const char* ProtoEnumToString(
 const char* ProtoEnumToString(sync_pb::TabNavigation::BlockedState state);
 const char* ProtoEnumToString(sync_pb::TabNavigation::PasswordState state);
 
+const char* ProtoEnumToString(
+    sync_pb::TranslateInteraction::Interaction interaction);
+
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_PROTOCOL_PROTO_ENUM_CONVERSIONS_H_