g directly into the path array.
   *
   * @param {!Array.<!Array.<string>>} path - A path in a CPU time
   * multidimensional tree view.
   * @returns {Object.<string, string>}
   */
  function decodePath_(path) {
    return {
      processType: path[0][0],
      threadType: path[1][0],
      railStage: path[2][0],
      initiatorType: path[2][1]
    };
  }

  /**
   * Returns a unique string representation of |path|.
   *
   * Paths are of the following form in CPU time multidimensional trees:
   *   [[pro