Define a minimum time for double tap in ChromeVox.

chrome/browser/resources/chromeos/chromevox/common/key_util.js

 // 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.
 
 /**
  * @fileoverview A collection of JavaScript utilities used to simplify working
  * with keyboard events.
  */
 
 
@@ skipping 100 matching lines @@
   } else {
     util.sequencing = false;
   }
 
   // Repeated keys pressed.
   var currTime = new Date().getTime();
   if (cvox.KeyUtil.isDoubleTapKey(keySequence) &&
       util.prevKeySequence &&
       keySequence.equals(util.prevKeySequence)) {
     var prevTime = util.modeKeyPressTime;
-    if (prevTime > 0 && currTime - prevTime < 300) {  // Double tap
+    var delta = currTime - prevTime;
+    if (prevTime > 0 && delta > 100 && delta < 300) {  // Double tap
       keySequence = util.prevKeySequence;
       keySequence.doubleTap = true;
       util.prevKeySequence = null;
       util.sequencing = false;
       // Resets the search key state tracked for ChromeOS because in OOBE,
       // we never get a key up for the key down (keyCode 91).
       if (cvox.ChromeVox.isChromeOS &&
           keyEvent.keyCode == cvox.KeyUtil.getStickyKeyCode()) {
         cvox.ChromeVox.searchKeyHeld = false;
       }
@@ skipping 363 matching lines @@
   key.doubleTap = true;
   for (var i = 0, keySeq; keySeq = cvox.KeySequence.doubleTapCache[i]; i++) {
     if (keySeq.equals(key)) {
       isSet = true;
       break;
     }
   }
   key.doubleTap = originalState;
   return isSet;
 };