Make Braille IME send space bar as an empty cell instead of letting propagate.

chrome/browser/resources/chromeos/braille_ime/externs.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 Externs for the braille IME.
  * @externs
  */
 
 /**
@@ skipping 123 matching lines @@
 
 /** @type {boolean} */
 ChromeKeyboardEvent.prototype.altKey;
 
 /** @type {boolean} */
 ChromeKeyboardEvent.prototype.ctrlKey;
 
 /** @type {boolean} */
 ChromeKeyboardEvent.prototype.shiftKey;
 
+/** @type {boolean} */
+ChromeKeyboardEvent.prototype.capsLock;
+
 /**
  * @constructor
  */
 function InputContext() {}
 
 /** @type {number} */
 InputContext.prototype.contextID;
 
 /** @type {string} */
 InputContext.prototype.type;
 
 /**
  * @typedef {{
  *     id: string,
  *     label: (string|undefined),
  *     style: string,
  *     visible: (boolean|undefined),
  *     checked: (boolean|undefined),
  *     enabled: (boolean|undefined)
  * }}
  */
 chrome.input.ime.MenuItem;
 
 /**
  * @type {Object}
  */
 var localStorage;