diff --git a/include/gui/SurfaceTextureClient.h b/include/gui/SurfaceTextureClient.h
index e7c6e24..6ce44fc 100644
--- a/include/gui/SurfaceTextureClient.h
+++ b/include/gui/SurfaceTextureClient.h
@@ -80,6 +80,7 @@
     int setUsage(uint32_t reqUsage);
 
     void freeAllBuffers();
+    int getSlotFromBufferLocked(android_native_buffer_t* buffer) const;
 
     int getConnectedApi() const;