docs: public float rotateToFaceCamera(final Widget widget) {
          final float yaw = getMainCameraRigYaw();
          GVRTransform t = getMainCameraRig().getHeadTransform();
          widget.rotateWithPivot(t.getRotationW(), 0, t.getRotationY(), 0, 0, 0, 0);
          return yaw;
      }