Initial support for accessible text fields and focus tracking in ARC++

chrome/browser/resources/chromeos/chromevox/cvox2/background/earcon_engine.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 is the low-level class that generates ChromeVox's
  * earcons. It's designed to be self-contained and not depend on the
  * rest of the code.
  */
 
@@ skipping 178 matching lines @@
  * The chain is hooked up to the destination automatically, so you
  * just need to connect your source to the return value from this
  * method.
  *
  * @param {{gain: (number | undefined),
  *          pan: (number | undefined),
  *          reverb: (number | undefined)}} properties
  *     An object where you can override the default
  *     gain, pan, and reverb, otherwise these are taken from
  *     masterVolume, masterPan, and masterReverb.
- * @return {AudioNode} The filters to be applied to all sounds, connected
+ * @return {!AudioNode} The filters to be applied to all sounds, connected
  *     to the destination node.
  */
 EarconEngine.prototype.createCommonFilters = function(properties) {
   var gain = this.masterVolume;
   if (properties.gain) {
     gain *= properties.gain;
   }
   var gainNode = this.context_.createGain();
   gainNode.gain.value = gain;
   var first = gainNode;
@@ skipping 519 matching lines @@
 
   // Clamp.
   x = Math.min(Math.max(x, 0.0), 1.0);
 
   // Map to between the negative maximum pan x position and the positive max x
   // pan position.
   x = (2 * x - 1) * EarconEngine.MAX_PAN_ABS_X_POSITION;
 
   this.masterPan = x;
 };