Show the message 'No files match "abc"' if the search results are empty.

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.col-resize * {
   cursor: col-resize !important;
 }
 
 /* Outer frame of the dialog. */
 body {
@@ skipping 1265 matching lines @@
   100% { opacity: 1; }
 }
 
 :hover > .tooltip {
   -webkit-animation-duration: 800ms;
   -webkit-animation-iteration-count: 1;
   -webkit-animation-name: tooltip-show;
   -webkit-animation-timing-function: linear;
   opacity: 1;
 }
+
+#no-search-results {
+  bottom: 0;
+  left: 0;
+  padding: 10px;
+  position: absolute;
+  right: 0;
+  top: 28px;  /* Leave room for the file list header. */
+}