public void onTreeUpdate() {
        mDetached = (getChildCount() == 0 && getParent() == null);
        if (mDetached && mDropped && !mTornDown) {
            onTearDown();
        }
    }
Invoked when a view is attached or detached from the React
view tree. We check if its fully detached (no parents or children),
to mark its detached status.
android/viro_bridge/src/main/java/com/viromedia/bridge/component/VRTComponent.java