title: XAML WebView binding to HTML source not working
body: <p>I have a XAML page layout defined that includes a <code>WebView</code> populated from an HTML string:</p>
  
  <pre><code>&lt;WebView HorizontalOptions="Fill" VerticalOptions="FillAndExpand"&gt;
      &lt;WebView.Source&gt;
          &lt;HtmlWebViewSource Html="{Binding Flag.Description}" /&gt;
  &lt;!--    &lt;HtmlWebViewSource Html="&amp;lt;html&gt;&amp;lt;body&gt;&amp;lt;p&gt;The HTML string.&amp;lt;/p&gt;&amp;lt;/body&gt;&amp;lt;/html&gt;" /&gt;--&gt;
      &lt;/WebView.Source&gt;
  &lt;/WebView&gt;
  </code></pre>
  
  <p>When I hard code the string into the XAML it displays correctly, but it will not bind to the <code>Flag.Description</code> string. The XAML includes a couple of labels that bind correctly but I can't find any reason why the WebView source isn't binding correctly.</p>