Improve speech contextual announcements and startCallback synchronization

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 10 matching lines @@
   __proto__: ChromeVoxNextE2ETest.prototype,
 
   /** @override */
   setUp: function() {
     ChromeVoxState.instance.toggleNext(true);
     window.RoleType = chrome.automation.RoleType;
     window.doCmd = this.doCmd;
 
     // Reset notifications so only explicit mode changes can cause them to trigger.
     Notifications.reset();
+    this.forceContextualLastOutput();
   },
 
   /**
    * @return {!MockFeedback}
    */
   createMockFeedback: function() {
     var mockFeedback = new MockFeedback(this.newCallback(),
                                         this.newCallback.bind(this));
     mockFeedback.install();
     return mockFeedback;
@@ skipping 1117 matching lines @@
     <input type="text"></input>
   */}, function(root) {
     this.listenOnce(root, 'focus', function(e) {
       var focus = ChromeVoxState.instance.currentRange.start.node;
       assertEquals(RoleType.textField, focus.role);
       assertTrue(focus.state.focused);
     });
     doCmd('nextEditText')();
   });
 });