src/modules/Progress.php
public function init()
    {
        parent::init();
        if ($this->percent !== null) {
            $this->clientOptions['percent'] = $this->percent;
        }
        if (!empty($this->size)) {
            Html::addCssClass($this->options, $this->size);
        }
        Html::addCssClass($this->barOptions, 'bar');
        Html::addCssClass($this->options, 'progress');
    }
public function init()
    {
        parent::init();
        if ($this->percent !== null) {
            $this->clientOptions['percent'] = $this->percent;
        }
        if (!empty($this->size)) {
            Html::addCssClass($this->options, $this->size);
        }
        Html::addCssClass($this->barOptions, 'bar');
        Html::addCssClass($this->options, 'progress');
    }
Initializes the widget.
If you override this method, make sure you call the parent implementation first.