CefSharp：获取渲染文本

Question

我需要获取网页中包含的渲染文本（没有html标签的纯文本）。

假设：

<p>The <b>Moon</b> is an <a href="/wiki/Astronomical_object" title="Astronomical object">astronomical body</a> that <a href="/wiki/Orbit" title="Orbit">orbits</a> <a href="/wiki/Planet" title="Planet">planet</a> <a href="/wiki/Earth" title="Earth">Earth</a>, being Earth's only <a href="/wiki/Claimed_moons_of_Earth#Temporary_satellites" title="Claimed moons of Earth">permanent</a> <a href="/wiki/Natural_satellite" title="Natural satellite">natural satellite</a>.

我应该得到：

The Moon is an astronomical body that orbits planet Earth, being Earth's only permanent natural satellite.

我试过这个，但我只能得到HTML代码：

private static ChromiumWebBrowser wb;

public static void Start()
{
  const string testUrl = "https://en.wikipedia.org/wiki/Moon";

  var settings = new CefSettings()
  {
    CachePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "CefSharp\\Cache")
  };

  Cef.Initialize(settings, performDependencyCheck: true, browserProcessHandler: null);
  wb = new ChromiumWebBrowser(testUrl);
  wb.FrameLoadEnd += browser_FrameLoadEnd;
}

static void browser_FrameLoadEnd(object sender, FrameLoadEndEventArgs e)
{
    if (e.Frame.IsMain)
    {
        wb.GetSourceAsync().ContinueWith(taskHtml =>
        {
            String html = taskHtml.Result;
            Console.Write(html);
        });
    }
}