Make cvox2 feedback more robust when focusing a text field.

chrome/browser/resources/chromeos/chromevox/testing/mock_feedback.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview This file contains the |MockFeedback| class which is a
  * combined mock class for speech and braille feedback.  A test that uses
  * this class may add expectations for speech utterances and braille display
  * content to be output.  The |install| method sets appropriate mock classes
  * as the |cvox.ChromeVox.tts| and |cvox.ChromeVox.braille| objects,
@@ skipping 123 matching lines @@
           return !!MockFeedback.matchAndConsume_(
               text, {}, this.pendingUtterances_);
         }.bind(this),
         toString: function() { return 'Speak \'' + text + '\''; }
       });
     }.bind(this));
     return this;
   },
 
   /**
+   * Adds an expectation that the next spoken utterances do *not* match
+   * the given arguments.
+   *
+   * This is only guaranteed to work for the immediately following utterance.
+   * If you use it to check an utterance other than the immediately following
+   * one the results may be flaky.
+   *
+   * @param {...(string|RegExp)} var_args One or more utterance to add as
+   *     negative expectations.
+   * @return {MockFeedback} |this| for chaining
+   */
+  expectNextSpeechUtteranceIsNot: function() {
+    assertFalse(this.replaying_);
+    Array.prototype.forEach.call(arguments, function(text) {
+      this.pendingActions_.push({
+        perform: function() {
+          if (this.pendingUtterances_.length == 0)
+            return false;
+          if (MockFeedback.matchAndConsume_(
+                  text, {}, this.pendingUtterances_)) {
+            throw new Error('Got disallowed utterance "' + text + '".');
+          }
+          return true;
+        }.bind(this),
+        toString: function() { return 'Do not speak \'' + text + '\''; }
+      });
+    }.bind(this));
+    return this;
+  },
+
+  /**
    * Adds an expectation for braille output.
    * @param {string|RegExp} text
    * @param {Object=} opt_props Additional properties to match in the
    *     |NavBraille|
    * @return {MockFeedback} |this| for chaining
    */
   expectBraille: function(text, opt_props) {
     assertFalse(this.replaying_);
     var props = opt_props || {};
     this.pendingActions_.push({
@@ skipping 169 matching lines @@
   }
   if (candidate) {
     var consumed = pending.splice(0, i + 1);
     consumed.forEach(function(item) {
       if (item.callback)
         item.callback();
     });
   }
   return candidate;
 };