fix circular dependency libnativewindow <-> libui

Bug: 37647680
Bug: 37648355
Test: compile, manual
Change-Id: I9631beea52e23ebb519411f943c6f5062aedd2e5
diff --git a/libs/gui/tests/IGraphicBufferProducer_test.cpp b/libs/gui/tests/IGraphicBufferProducer_test.cpp
index aa071f6..bcfc91c 100644
--- a/libs/gui/tests/IGraphicBufferProducer_test.cpp
+++ b/libs/gui/tests/IGraphicBufferProducer_test.cpp
@@ -29,6 +29,8 @@
 #include <gui/BufferQueue.h>
 #include <gui/IProducerListener.h>
 
+#include <system/window.h>
+
 #include <vector>
 
 #define ASSERT_OK(x) ASSERT_EQ(OK, (x))