function* generator()
        {
            for (var i = 0; i < types.length; ++i) {
                var invalidationList = invalidations[types[i]] || [];
                for (var j = 0; j < invalidationList.length; ++j)
                    yield invalidationList[j];
            }
        }
@param {!Array.<string>=} types
@return {!Iterator.<!WebInspector.InvalidationTrackingEvent>}