diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index 59b62fe..0d1a69b 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -51,6 +51,7 @@
 
 namespace android {
 
+using gui::CallbackId;
 using gui::FocusRequest;
 using gui::WindowInfoHandle;