Use relative bounding boxes throughout Chrome accessibility

chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Include test fixture.
 GEN_INCLUDE(['../../testing/chromevox_next_e2e_test_base.js',
              '../../testing/assert_additions.js']);
 
 GEN_INCLUDE(['../../testing/mock_feedback.js']);
 
@@ skipping 63 matching lines @@
 
   iframesDoc: function() {/*!
     <p>start</p>
     <button>Before</button>
     <iframe srcdoc="<button>Inside</button><h1>Inside</h1>"></iframe>
     <button>After</button>
   */},
 
   disappearingObjectDoc: function() {/*!
     <p>start</p>
-    <article>
+    <div role="group">
       <p>Before1</p>
       <p>Before2</p>
       <p>Before3</p>
-    </article>
-    <article>
+    </div>
+    <div role="group">
       <p id="disappearing">Disappearing</p>
-    </article>
-    <article>
+    </div>
+    <div role="group">
       <p>After1</p>
       <p>After2</p>
       <p>After3</p>
-    </article>
     </div>
     <div id="live" aria-live="polite"></div>
     <div id="delete" role="button">Delete</div>
     <script>
       document.getElementById('delete').addEventListener('click', function() {
         var d = document.getElementById('disappearing');
         d.parentElement.removeChild(d);
         document.getElementById('live').innerText = 'Deleted';
       });
     </script>
@@ skipping 1018 matching lines @@
           .call(doCmd('nextHeading' + level))
           .expectSpeech('No next level ' + level + ' heading.')
           .call(doCmd('previousHeading' + level))
           .expectSpeech('No previous level ' + level + ' heading.');
     };
     for (var i = 1; i <= 6; i++)
       makeLevelAssertions(i);
     mockFeedback.replay();
   });
 });