效果：开始的时候会显示几秒，之后就不会再显示了

<!--浏览器-->
<cefSharpWPF:ChromiumWebBrowser Name="webBrowser"  Grid.Row="0" >
</cefSharpWPF:ChromiumWebBrowser>

public MainWindow()
{
    InitializeComponent();

    webBrowser.FrameLoadEnd += OnBrowserFrameLoadEnd;
}

private void OnBrowserFrameLoadEnd(object sender, FrameLoadEndEventArgs args)
{
    if (args.Frame.IsMain)
    {
        args
            .Browser
            .MainFrame
            .ExecuteJavaScriptAsync(
            "document.body.style.overflow = 'hidden'");
    }
}

参考资料：
https://stackoverflow.com/questions/43742596/how-can-i-get-cefsharp-to-hide-both-the-vertical-and-horizontal-scrollbars-when