Cannot switch to Webview in Facebook application

I’m using Appium to check web articles that are shared in step are:

  1. open Facebook application in real device (Android)
  2. find the article that I need and click to enter it.
  3. try to switch to Webview to check some elements inside the article,

But when I debug I see only NATIVE APP context.

However , When I check this page using UI Automator Viewer, I see the article appears in the class “android.webkit.WebView”.

Can you please tell me how I can switch to a Webview in such a case?
The Appium version that I’m using is 1.4.16