Use category flush for focus events.

chrome/browser/resources/chromeos/chromevox/cvox2/background/keyboard_handler.js

 // Copyright 2016 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 ChromeVox keyboard handler.
  */
 
 goog.provide('BackgroundKeyboardHandler');
 
@@ skipping 20 matching lines @@
   onKeyDown: function(evt) {
     evt.stickyMode = cvox.ChromeVox.isStickyModeOn() && cvox.ChromeVox.isActive;
     if (cvox.ChromeVox.passThroughMode)
       return false;
 
     if (ChromeVoxState.instance.mode != ChromeVoxMode.CLASSIC &&
         !cvox.ChromeVoxKbHandler.basicKeyDownActionsListener(evt)) {
       evt.preventDefault();
       evt.stopPropagation();
     }
-    Output.flushNextSpeechUtterance();
+    Output.forceModeForNextSpeechUtterance(cvox.QueueMode.FLUSH);
     return false;
   },
 
   /**
    * Handles key up events.
    * @param {Event} evt The key down event to process.
    * @return {boolean} True if the default action should be performed.
    */
   onKeyUp: function(evt) {
     // Reset pass through mode once a keyup (not involving the pass through key)
@@ skipping 33 matching lines @@
       if (oldMode &&
           oldMode != ChromeVoxMode.CLASSIC &&
           oldMode != ChromeVoxMode.COMPAT) {
         // The user's configured key map gets wiped here; this is consistent
         // with previous behavior when switching keymaps.
         window['prefs'].switchToKeyMap('keymap_next');
       }
     }
   }
 };