code: public static synchronized GVRAnimationEngine getInstance(
              GVRContext gvrContext) {
          if (sInstance == null) {
              sInstance = new GVRAnimationEngine(gvrContext);
          }
          return sInstance;
      }
docs: The animation engine is an optional part of GVRF: You do have to call
  {@code getInstance()} to lazy-create the singleton.
  
  @param gvrContext
  current GVR context