fix circular dependency libnativewindow <-> libui

Bug: 37647680
Bug: 37648355
Test: compile, manual
Change-Id: I9631beea52e23ebb519411f943c6f5062aedd2e5
diff --git a/libs/gui/tests/BufferQueue_test.cpp b/libs/gui/tests/BufferQueue_test.cpp
index 60c1277..4220aaf 100644
--- a/libs/gui/tests/BufferQueue_test.cpp
+++ b/libs/gui/tests/BufferQueue_test.cpp
@@ -32,6 +32,8 @@
 #include <utils/String8.h>
 #include <utils/threads.h>
 
+#include <system/window.h>
+
 #include <gtest/gtest.h>
 
 #include <thread>