It seems that the fetched title is the whole page content. As my testing experiences, if I always leave the title empty, it will fetch the whole page content.

C  134s Main  [FAIL] org.xwalk.core.xwview.test.ExtensionBroadcastTest#testExtensionBroadcast:
C  134s Main  junit.framework.ComparisonFailure: expected:<[Pass]> but was:<[data:text/html,<html>  <head>    <title></title>  </head>  <body>    <iframe id="subFrame"></iframe>    <script>      var iframe = document.getElementById("subFrame");      // Write the iframe content. Might be better to put it into a separate html file.       iframe.contentDocument.write("<html>\n" +... } XXXXX   </script>  </body></html>]>