Adjust virtual keyboard size base on input method candidates.

chrome/browser/resources/keyboard/main.css

 /*
 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.
 */
 
 body {
   background: -webkit-linear-gradient(#131925, #04070B);
   color: white;
   margin: 0;
+  overflow: hidden;
   padding: 0;
   -webkit-user-select: none;
 }
 
 div.row {
   margin-top: 5px;
 }
 
 .ime {
   border: 1px solid gray;
@@ skipping 96 matching lines @@
 }
 
 .shift {
   background-image: url("shift.svg");
 }
 
 .hide {
   background-image: url("keyboard.svg");
 }