WEBP_FILTER_GRADIENT  222 third_party/libwebp/utils/filters.c       bins[WEBP_FILTER_GRADIENT][diff3] = 1;
WEBP_FILTER_GRADIENT   29 third_party/libwebp/utils/filters.h   WEBP_FILTER_LAST = WEBP_FILTER_GRADIENT + 1,  // end marker