Camera: BufferManager: Don't attach/detach on every frame

- Maintain separate count of attached buffers
- Only attach when new buffers need to be allocated
- Only detach when a buffer needs to be freed
- Fix missing notification initializations
- Remove warning that's always logged

Bug: 28695173
Change-Id: I38e997fa1e69c2b8743e43eed31a6a08a6f9cd7a
diff --git a/services/camera/libcameraservice/device3/Camera3DummyStream.h b/services/camera/libcameraservice/device3/Camera3DummyStream.h
index 97c0c96..7b48daa 100644
--- a/services/camera/libcameraservice/device3/Camera3DummyStream.h
+++ b/services/camera/libcameraservice/device3/Camera3DummyStream.h
@@ -54,6 +54,8 @@
 
     status_t         setTransform(int transform);
 
+    virtual status_t detachBuffer(sp<GraphicBuffer>* buffer, int* fenceFd);
+
     /**
      * Return if this output stream is for video encoding.
      */