Use a sound pool instead of a single audio tag.

ui/keyboard/resources/constants.js

 // Copyright (c) 2013 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.
 
 var RowAlignment = {
   STRETCH: "stretch",
   LEFT: "left",
   RIGHT: "right",
   CENTER: "center",
 }
@@ skipping 41 matching lines @@
  */
 var DEFAULT_KEY_WEIGHT_X = 100;
 
 /**
  * The default weight of a key in the Y direction.
  * @type {number}
  */
 var DEFAULT_KEY_WEIGHT_Y = 70;
 
 /**
+ * The default volume for keyboard sounds.
+ * @type {number}
+ */
+var DEFAULT_VOLUME = 0.2;
+
+/**
  * The top padding on each key.
  * @type {number}
  */
 // TODO(rsadam): Remove this variable once figure out how to calculate this
 // number before the key is rendered.
 var KEY_PADDING_TOP = 1;
 var KEY_PADDING_BOTTOM = 1;
 
 /**
- * The default volume for keyboard sounds.
+ * The size of the pool to use for playing audio sounds on key press. This is to
+ * enable the same sound to be overlayed, for example, when a repeat key is
+ * pressed.
  * @type {number}
  */
-var DEFAULT_VOLUME = 0.3;
+var SOUND_POOL_SIZE = 10;