title: Android webview onReceivedError() not called when webpage responds with error status
body: <p>onReceivedError() is called if the webview tries to load some non-existent page, but it is not called if the server/website chooses to respond with an error status, such as status 500.</p>
  
  <pre><code># Django returning status 500
  return HttpResponseServerError("returned status 500")
  </code></pre>
  
  <p>This response appears in the regular Chrome browser with status 500. However, the webview just loads it, never calling onReceivedError().</p>
  
  <p>How can the app/webview tell if the server is sending back an error status? I need to handle it like any error.</p>
  
  <p>Thanks!</p>