Merge "Revert "Call preserveSurfaces when detaching children."" into rvc-dev

        if (mSurfaceController != null) {

            mSurfaceController.detachChildren();

        }

        // If the children are detached, it means the app is exiting. We don't want to tear the

        // content down too early, otherwise we could end up with a flicker. By preserving the

        // current surface, we ensure the content remains on screen until the window is completely

        // removed. It also ensures that the old surface is cleaned up when started again since it

        // forces mSurfaceController to be set to null.

        preserveSurfaceLocked();

    }

    void setOffsetPositionForStackResize(boolean offsetPositionForStackResize) {