Jetpack::maybe_inline_style PHP Method

    public static function maybe_inline_style($tag, $handle)
    {
        global $wp_styles;
        $item = $wp_styles->registered[$handle];
        if (!isset($item->extra['jetpack-inline']) || !$item->extra['jetpack-inline']) {
            return $tag;
        }
        if (preg_match('# href=\'([^\']+)\' #i', $tag, $matches)) {
            $href = $matches[1];
            // Strip off query string
            if ($pos = strpos($href, '?')) {
                $href = substr($href, 0, $pos);
            }
            // Strip off fragment
            if ($pos = strpos($href, '#')) {
                $href = substr($href, 0, $pos);
            }
        } else {
            return $tag;
        }
        $plugins_dir = plugin_dir_url(JETPACK__PLUGIN_FILE);
        if ($plugins_dir !== substr($href, 0, strlen($plugins_dir))) {
            return $tag;
        }
        // If this stylesheet has a RTL version, and the RTL version replaces normal...
        if (isset($item->extra['rtl']) && 'replace' === $item->extra['rtl'] && is_rtl()) {
            // And this isn't the pass that actually deals with the RTL version...
            if (false === strpos($tag, " id='{$handle}-rtl-css' ")) {
                // Short out, as the RTL version will deal with it in a moment.
                return $tag;
            }
        }
        $file = JETPACK__PLUGIN_DIR . substr($href, strlen($plugins_dir));
        $css = Jetpack::absolutize_css_urls(file_get_contents($file), $href);
        if ($css) {
            $tag = "<!-- Inline {$item->handle} -->\r\n";
            if (empty($item->extra['after'])) {
                wp_add_inline_style($handle, $css);
            } else {
                array_unshift($item->extra['after'], $css);
                wp_style_add_data($handle, 'after', $item->extra['after']);
            }
        }
        return $tag;
    }