static parseRegion_(text) {
    const VttTextParser = shaka.text.VttTextParser;
    const parser = new shaka.util.TextParser(text);
    // The region string looks like this:
    // Region: id=fred width=50% lines=3 regionanchor=0%,100%
    //         viewportanchor=10%,90% scroll=up
    const region = new shaka.text.CueRegion();

    // Skip 'Region:'
    parser.readWord();
    parser.skipWhitespace();

    let word = parser.readWord();
    while (word) {
      if (!VttTextParser.parseRegionSetting_(region, word)) {
        shaka.log.warning(
            'VTT parser encountered an invalid VTTRegion setting: ', word,
            ' The setting will be ignored.');
      }
      parser.skipWhitespace();
      word = parser.readWord();
    }

    return region;
  }
Parses a string into a Region object.

@param {string} text
@return {!shaka.text.CueRegion}
@private