MD Downloads: use custom iconset

chrome/browser/resources/md_downloads/item.css

 /* Copyright 2015 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. */
 
 :host {
   display: flex;
   flex-direction: column;
 }
 
 #date {
@@ skipping 71 matching lines @@
 #content:not(.is-active) .icon {
   -webkit-filter: grayscale(100%);
   opacity: .5;
 }
 
 #danger-icon {
   height: 32px;
   width: 32px;
 }
 
-#danger-icon[icon='warning'] {
+#danger-icon[icon='downloads:warning'] {
   color: rgb(255, 193, 7);
 }
 
-#danger-icon[icon='remove-circle'] {
+#danger-icon[icon='downloads:remove-circle'] {
   color: rgb(244, 67, 54);
 }
 
 #name,
 #file-link,
 #url {
   max-width: 100%;
 }
 
 #name,
@@ skipping 97 matching lines @@
 }
 
 #incognito {
   bottom: 20px;
   content: -webkit-image-set(
       url(chrome://downloads/1x/incognito_marker.png) 1x,
       url(chrome://downloads/2x/incognito_marker.png) 2x);
   position: absolute;
   right: 10px;
 }