Fix ChromeVox next tests to fail instead of timing out where applicable.

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']);
 
 GEN_INCLUDE(['../../testing/mock_tts.js']);
 
 /**
@@ skipping 65 matching lines @@
       return root;
     }
     for (var i = 0; i < root.children.length; i++) {
       var found = findStatusTray(root.children[i]);
       if (found)
         return found;
     }
     return null;
   }
 
-  chrome.automation.getDesktop(function(root) {
-    var testButton = findStatusTray(root);
-    cvox.ChromeVox.tts.expectSpeech('Status tray', testDone);
-    testButton.focus();
-  });
+  chrome.automation.getDesktop(this.continueTest(
+      WhenTestDone.ASSERT,
+      function(root) {
+        var testButton = findStatusTray(root);
+        cvox.ChromeVox.tts.expectSpeech('Status tray', testDone);
+        testButton.focus();
+      }));
 });
 
 /** Tests feedback once a page loads. */
 TEST_F('BackgroundTest', 'InitialFeedback', function() {
   cvox.ChromeVox.tts.expectSpeech('start', function() {
     global.backgroundObj.onGotCommand('nextLine');
   }, true);
   cvox.ChromeVox.tts.expectSpeech('end', testDone, true);
 
   this.runWithDocument(function() {/*!
@@ skipping 90 matching lines @@
       }.bind(this), 0);
     }.bind(cvox.ChromeVox.tts);
 
     expect('start', doCmd('continuousRead'));
     expect('alpha Link', sendEndEvent);
     expect('beta Link', sendEndEvent);
     expect('Heading charlie', sendEndEvent);
     cvox.ChromeVox.tts.finishExpectations();
   }.bind(this));
 });