setInitialTextState_(initialVariant, initialTextStream) {
    // Check if we should show text (based on difference between audio and text
    // languages).
    if (initialTextStream) {
      goog.asserts.assert(this.config_, 'Must not be destroyed');
      if (shaka.util.StreamUtils.shouldInitiallyShowText(
          initialVariant.audio, initialTextStream, this.config_)) {
        this.isTextVisible_ = true;
      }
      if (this.isTextVisible_) {
        // If the cached value says to show text, then update the text displayer
        // since it defaults to not shown.
        this.textDisplayer_.setTextVisibility(true);
        goog.asserts.assert(this.shouldStreamText_(),
            'Should be streaming text');
      }
    } else {
      this.isTextVisible_ = false;
      this.textDisplayer_.setTextVisibility(false);
    }
    this.onTextTrackVisibility_();
  }
Decide during startup if text should be streamed/shown.
@private