Move Files.app files to ui/file_manager

chrome/browser/resources/file_manager/foreground/css/combobutton.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. */
-
-.buttonbar button.combobutton {
-  -webkit-box-align: stretch;
-  display: -webkit-box;
-}
-
-.buttonbar .combobutton > .action {
-  background-position: left center;
-  background-repeat: no-repeat;
-  background-size: 16px 16px;
-  padding-left: 21px;
-}
-
-.buttonbar .combobutton > .trigger {
-  border-left: solid 1px #dcdcdc;
-  margin-left: 8px;
-  margin-right: -8px;
-  width: 22px;
-}
-
-.buttonbar .combobutton:not([multiple]) > .trigger {
-  display: none;
-}
-
-.buttonbar .combobutton > div > span.disclosureindicator {
-  -webkit-transform: rotate(90deg);
-}
-
-.buttonbar .combobutton[hidden] {
-  display: none;
-}