Remove dangling chrome://theme/IDR_CLOSE_BAR* references

chrome/browser/resources/ntp4/new_tab.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.
  */
 
 html {
   font-family: segoe ui, arial, helvetica, sans-serif;
   font-size: 14px;
   /* It's necessary to put this here instead of in body in order to get the
      background-size of 100% to work properly */
@@ skipping 48 matching lines @@
 
 #notification .close-button {
   vertical-align: middle;
   -webkit-margin-start: 0.5em;
 }
 
 .close-button {
   background: no-repeat;
   background-color: transparent;
   /* TODO(estade): this should animate between states. */
-  background-image: url('chrome://theme/IDR_CLOSE_BAR');
+  background-image: url('../../../../ui/resources/close_bar.png');
   border: 0;
   cursor: default;
   display: inline-block;
   height: 16px;
   padding: 0;
   width: 16px;
 }
 
 .close-button:hover,
 .close-button:focus {
-  background-image: url('chrome://theme/IDR_CLOSE_BAR_H');
+  background-image: url('../../../../ui/resources/close_bar_h.png');
 }
 
 .close-button:active {
-  background-image: url('chrome://theme/IDR_CLOSE_BAR_P');
+  background-image: url('../../../../ui/resources/close_bar_p.png');
 }
 
 .linkButton {
   color: #06C;
   cursor: pointer;
   display: inline-block;
   text-decoration: underline;
   -webkit-margin-start: 0.5em;
 }
 
@@ skipping 220 matching lines @@
   padding: 0;
   position: absolute;
   margin: 0;
   max-width: 150px;
   min-width: 90px;
   outline: none;
   top: 0;
   z-index: 5;
   -webkit-transition: width 150ms, right 150ms, background-color 150ms;
 }