Remove WebUI NTP on Android.

chrome/browser/resources/ntp_android/opentabs_tablet.css

-/* Copyright (c) 2012 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[device='tablet'] #open_tabs_container {
-  padding-bottom: 40px;
-}
-
-body[device='tablet'] #open_tabs_container .page-list>div {
-  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.16);
-  margin: 40px auto 0 auto;
-  max-width: 550px;
-  min-width: 500px;
-}
-
-@media only screen and (min-device-width: 700px) {
-  body[device='tablet'] #open_tabs_container .page-list>div {
-    max-width: 650px;
-  }
-}
-
-body[device='tablet'] .session-children-container>div:last-child {
-  border-bottom: none;
-}
-
-body[device='tablet'] #open_tabs_container .session-header .list-item {
-  background: #F2F2F2;
-  border-bottom: 1px solid #E7E7E7;
-  color: #777;
-  font-size: 0.8em;
-  padding: 20px 0 20px 0;
-}
-
-body[device='tablet'] #open_tabs_container .list-item {
-  background: #FAFAFA;
-  border: 1px solid #E0E0E0;
-  border-bottom: none;
-}
-
-body[device='tablet'] #open_tabs_container .list-item-active,
-body[device='tablet'] #open_tabs_container .session-header
-    .list-item.list-item-active {
-  -webkit-tap-highlight-color: transparent;
-  background: rgba(51, 181, 229, 0.4);
-}
-
-body[device='tablet'] .session-name {
-  color: #333;
-  font-size: 1.1em;
-  font-weight: bold;
-  line-height: 1.8em;
-}
-
-body[device='tablet'] .session-last-synced {
-  font-weight: normal;
-}
-
-body[device='tablet'] #open_tabs_container .session-children-container
-    .list-item:first-child {
-  border-top: none;
-}