Add lots of 2x assets

chrome/browser/resources/bookmark_manager/css/bmm.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,
 body {
   cursor: default;
   height: 100%;
   margin: 0;
   overflow: hidden;
@@ skipping 163 matching lines @@
 html[dir=rtl] list > .folder > .label {
   background-image: url(
       '../../../../../ui/resources/default_100_percent/folder_closed_rtl.png');
 }
 
 <if expr="is_macosx">
 list > .folder > .label,
 .tree-label,
 .tree-row[may-have-children] > .tree-label,
 .tree-item[expanded] > .tree-row > .tree-label {
-  background-image: url('../../../../app/theme/bookmark_bar_folder_mac.png');
+  background-image: url('../../../../app/theme/default_100_percent/bookmark_bar_folder_mac.png');
 }
 </if>
 
 .main {
   bottom: 0;
   display: -webkit-box;
   left: 0;
   position: absolute;
   right: 0;
   top: 79px;
@@ skipping 110 matching lines @@
               no-repeat right center;
   border: 0;
   font: inherit;
   padding-bottom: 0;
   padding-top: 0;
 }
 
 html[dir=rtl] .summary button {
   background-position: left center;
 }