Moved mobile activation into its own modal dialog

chrome/browser/resources/file_manager/css/dialogs.css

-/*
- * Copyright (c) 2011 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.
- */
-
-.cr-dialog-container {
-  position: absolute;
-  -webkit-user-select: none;
-  top: 0;
-  left: 0;
-  height: 100%;
-  width: 100%;
-
-  background: -webkit-radial-gradient(rgba(127, 127, 127, 0.5),
-                                      rgba(127, 127, 127, 0.5) 35%,
-                                      rgba(0, 0, 0, 0.7));
-  opacity: 0;
-  -webkit-transition: opacity 0.25s linear;
-  overflow: hidden;
-
-  z-index: 9999;
-}
-
-.cr-dialog-frame {
-  position: absolute;
-  display: -webkit-box;
-  -webkit-box-orient: vertical;
-  -webkit-box-shadow: 5px 5px 5px rgba(100, 100, 100, 0.5);
-
-  -webkit-transition-duration:  0.25s;
-  -webkit-transition-property: none;
-
-  min-width: 25%;
-  max-width: 75%;
-  border: 1px #aaa solid;
-  border-radius: 2px;
-  background-color: white;
-  padding: 15px;
-}
-
-.cr-dialog-text {
-  padding-bottom: 10px;
-}
-
-.cr-dialog-frame input {
-  -webkit-box-sizing: border-box;
-  width: 100%;
-}
-
-.cr-dialog-buttons {
-  display: -webkit-box;
-  -webkit-box-orient: horizontal;
-  padding-top: 10px;
-  -webkit-box-pack: end;
-}