Fix broken build for more tests

Change-Id: I7bdd12a833233724805d01d993541ee05caa9bf6
diff --git a/libs/gui/tests/BufferQueue_test.cpp b/libs/gui/tests/BufferQueue_test.cpp
index b859fcb..5aa34a5 100644
--- a/libs/gui/tests/BufferQueue_test.cpp
+++ b/libs/gui/tests/BufferQueue_test.cpp
@@ -72,6 +72,7 @@
 struct DummyConsumer : public BnConsumerListener {
     virtual void onFrameAvailable() {}
     virtual void onBuffersReleased() {}
+    virtual void onSidebandStreamChanged() {}
 };
 
 TEST_F(BufferQueueTest, AcquireBuffer_ExceedsMaxAcquireCount_Fails) {