[NTP] Mobile friendly buttons on snippets internals.

chrome/browser/resources/snippets_internals.css

 /* Copyright 2016 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. */
 
 html {
   font-size: 20px;
 }
 
 #info > div {
   width: 100%;
@@ skipping 60 matching lines @@
   margin-bottom: 0.5em;
 }
 
 #last-json-text {
   border: 1px solid black;
   color: gray;
   font-size: 90%;
   padding: 4px;
   word-break: break-all;
 }
+
+button {
+  min-height: 30px;
+}
+
+.vertical-buttons > button {
+  float: left;
+  margin-right: 5px;
+  max-width: 100px;
+  min-height: 40px;
+}