DRAFT: Add setKeyboardVisibility API.

ui/keyboard/resources/layout_us.js

 // Copyright (c) 2011 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 simple English virtual keyboard implementation.
  */
 
 /**
  * All keys for the rows of the keyboard.
@@ skipping 34 matching lines @@
     new Key(C('b'), C('B'), C(':'), C('.')),
     new Key(C('n'), C('N'), C(';'), C(' ')),
     new Key(C('m'), C('M'), C('_'), C(' ')),
     new SvgKey('backspace', 'Backspace', true /* repeat */)
   ],
   [
     new SymbolKey(),
     new SpecialKey('comma', ',', ','),
     new SpecialKey('space', ' ', 'Spacebar'),
     new SpecialKey('period', '.', '.'),
-    new SvgKey('return', 'Enter')
+    new SvgKey('return', 'Enter'),
+    new HideKeyboardKey()
   ]
 ];
 
 // Add layout to KEYBOARDS, which is defined in common.js
 KEYBOARDS['us'] = {
   'definition': KEYS_US,
   'aspect': 2.00,
 };