anchor.diff:      }
   
       if (glIndexList != null) {
  +      context._bindIndexList(glIndexList);
  +
         final indexList = glIndexList.indexList;
   
         if (indexList.indexSize == IndexSize.unsignedByte) {
  
positive.code:         glPrimitives.vao = vao;
        }
      } else {
        context._bindIndexList(glIndexList);
  
        // TODO: find better way than creating a new set every time.
        final unusedAttribLocations = context._enabledAttributeLocations.toSet();
  
  
negative.code: 
          context._vaoExtension.bindVertexArray(vao);
  
          final attributes = glProgram.attributes;
          final attributesLength = attributes.length;
          final tables = new Set<AttributeDataTable>();
  