message: sample-gltf-viewer: fix ColorGrading JNI assert
diff: @@ -183,7 +183,7 @@ public class AutomationEngine {
  // so there is no need to call Engine#destroyColorGrading here.
  long nativeCg = nGetColorGrading(mNativeObject, engine.getNativeObject());
  if (mColorGrading == null || mColorGrading.getNativeObject() != nativeCg) {
  - mColorGrading = new ColorGrading(nativeCg);
  + mColorGrading = nativeCg == 0 ? null : new ColorGrading(nativeCg);
  }
  return mColorGrading;
  }
  