code: function ownProperties(constructor) {
     if (!constructor.hasOwnProperty(JSCompiler_renameProperty('__ownProperties', constructor))) {
       let props = null;
  
       if (constructor.hasOwnProperty(JSCompiler_renameProperty('properties', constructor)) && constructor.properties) {
         props = normalizeProperties(constructor.properties);
       }
  
       constructor.__ownProperties = props;
     }
     return constructor.__ownProperties;
   }
docs: Returns a memoized version of the `properties` object for the
  given class. Properties not in object format are converted to at
  least {type}.
  
  @param {PropertiesMixinConstructor} constructor PropertiesMixin constructor
  @return {Object} Memoized properties object