[New Tab Page] Local NTP: bound the size of favicon image.

chrome/browser/resources/local_ntp/most_visited_single.css

 /* 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. */
 
 body {
   -webkit-user-select: none;
   background: none transparent;
   color: #323232;
   margin: 0;
   overflow: hidden;
@@ skipping 350 matching lines @@
 }
 
 .mv-favicon.failed-favicon {
   background-image: -webkit-image-set(
       url(chrome-search://local-ntp/images/ntp_default_favicon.png) 1x,
       url(chrome-search://local-ntp/images/ntp_default_favicon.png@2x) 2x);
   background-repeat: no-repeat;
   background-size: 16px 16px;
 }
 
+.mv-favicon img {
+  height: 100%;
+  width: 100%;
+}
+
 .mv-favicon.failed-favicon img {
   display: none;
 }