code: public static BitmapTextureCallback wrapCallback(
              ResourceCache<GVRImage> cache, BitmapTextureCallback callback) {
          return new BitmapTextureCallbackWrapper(cache, callback);
      }
docs: Wrap the callback, to cache the
  {@link BitmapTextureCallback#loaded(GVRHybridObject, GVRAndroidResource)
  loaded()} resource