clearWindows_(windowsBitmap, pts) {
    const parsedClosedCaptions = [];

    // Clears windows from the 8 bit bitmap.
    for (const windowId of this.getSpecifiedWindowIds_(windowsBitmap)) {
      // If window visible and being cleared, emit buffer and reset start time!
      const window = this.windows_[windowId];
      if (window.isVisible()) {
        const newParsedClosedCaption =
            window.forceEmit(pts, this.serviceNumber_);
        if (newParsedClosedCaption) {
          parsedClosedCaptions.push(newParsedClosedCaption);
        }
      }
      window.resetMemory();
    }
    return parsedClosedCaptions;
  }
@param {number} windowsBitmap
@param {number} pts
@return {!Array<shaka.extern.ICaptionDecoder.ClosedCaption>}
@private