Add a warning for the deprecation of content-initiated data URL navigations

third_party/WebKit/LayoutTests/fast/dom/Window/resources/file-origin-window-open-frame.html

 <script>
 window.addEventListener('message', function () {
   var exc = null;
   try {
     newWindow.document;
   } catch (e) {
     exc = e;
   }
   top.postMessage(exc ? '' + exc : null, '*');
 });
-newWindow = window.open('data:text/html,<script>opener.postMessage("runTest","*");</scr' + 'ipt>');
+newWindow = window.open('file-origin-window-open-popup.html');
 </script>