function filterString(matchedStringIndexes, string, index)
        {
            if (string.indexOf(query) !== -1)
                matchedStringIndexes.add(index);
            return matchedStringIndexes;
        }
@param {!WebInspector.HeapSnapshotCommon.SearchConfig} searchConfig
@param {!WebInspector.HeapSnapshotCommon.NodeFilter} nodeFilter
@return {!Array.<number>}