ntp: remove ntp3 resources

chrome/browser/resources/ntp4/apps_page.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.
  */
 
 .app {
   position: absolute;
   text-align: center;
 }
 
@@ skipping 143 matching lines @@
 .g-button-basic {
   border-width: 6px 10px 12px 6px;
   color: #fff !important;
   display: inline-block;
   font-size: 1.3em;
   font-weight: bold;
   padding: 2px 10px;
   text-align: center;
   text-decoration: none;
   white-space: nowrap;
-  -webkit-border-image: url('../ntp/g-button-chocobo.png') 6 10 12 6;
+  -webkit-border-image: url('./images/app_promo_button.png') 6 10 12 6;
 }
 
 .app .invisible {
   visibility: hidden;
 }