setTextWatermark(text, options) {
    if (text && !this.watermark_ && this.videoContainer_ && this.controls_) {
      this.watermark_ = new shaka.ui.Watermark(
          this.videoContainer_, this.controls_);
    }
    if (this.watermark_) {
      this.watermark_.setTextWatermark(text, options);
    }
  }
@param {string} text
@param {?shaka.ui.Watermark.Options=} options
@export