Fix legacy UI in Files.app.

chrome/browser/resources/file_manager/css/file_manager.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 {
   height: 100%;
 }
 
 html.col-resize * {
   cursor: col-resize !important;
@@ skipping 696 matching lines @@
   cursor: pointer;
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
 }
 
 body[new-ui] .breadcrumb-path:not(.breadcrumb-last) {
   -webkit-app-region: no-drag;
 }
 
-#search-breadcrumbs .breadcrumb-path {
+body:not([new-ui]) #search-breadcrumbs .breadcrumb-path {
   color: #888;
 }
 
-#search-breadcrumbs .breadcrumb-path:hover {
+body[new-ui] #search-breadcrumbs .breadcrumb-path {
+  color: #969696;
+}
+
+body[new-ui] #search-breadcrumbs .breadcrumb-path:hover,
+body:not([new-ui]) #search-breadcrumbs .breadcrumb-path:hover {
   color: #666;
 }
 
 /* The final breadcrumb, representing the current directory. */
-.breadcrumb-last {
+body[new-ui] #search-breadcrumbs .breadcrumb-path.breadcrumb-last {
+  color: #141414;
+  cursor: default;
+}
+
+body:not([new-ui]) .breadcrumb-last {
   color: black;
   cursor: default;
 }
 
 /* The > arrow between breadcrumbs. */
 
 .breadcrumbs .separator {
   background-image: -webkit-image-set(
     url('../images/files/ui/breadcrumb-separator.png') 1x,
     url('../images/files/ui/2x/breadcrumb-separator.png') 2x);
@@ skipping 1489 matching lines @@
 body[new-ui] #iframe-drag-area {
   -webkit-app-region: drag;
   height: 45px;
   left: 64px;
   position: absolute;
   right: 70px;
   top: 0;
   width: auto;
   z-index: 101;
 }