rse a multidimensional tree view and report CPU
   * percentage and CPU time from the tree as histograms.
   */
  class CpuTimeTreeDataReporter {
    constructor() {
      this.visitedSet_ = new Set();
    }

    /**
     * Extracts CPU percentage and CPU time values from |node| located at |path|
     * and adds values as histograms to |this.histogramSet_|. Each value is
     * added as a single sample histogram.
     *
     * @param {!tr.b.MultiDimensionalViewNode} node
     * @param {!Array.<!Array.<strin