Added a DummyConsumer for use with BufferQueue.

The DummyConsumer is a consumer that can connect to BufferQueue
that does nothing.  It is required as BufferQueue checks
if a consumer is connected.  Also fixes a bug where SurfaceTexture
was reusing old texture slots.

Bug: 6172739
Change-Id: I5e7a118dd4d07807ba4c763200242b5ee7d3412b
diff --git a/libs/gui/Android.mk b/libs/gui/Android.mk
index 2f4ac62..8bda3aa 100644
--- a/libs/gui/Android.mk
+++ b/libs/gui/Android.mk
@@ -21,6 +21,7 @@
 	LayerState.cpp \
 	Surface.cpp \
 	SurfaceComposerClient.cpp \
+	DummyConsumer.cpp
 
 LOCAL_SHARED_LIBRARIES := \
 	libcutils \