[File Manager] Better Google Drive promo layout in Open/Save dialogs

chrome/browser/resources/file_manager/css/gdrive_welcome.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. */
 
 /* Google Drive welcome banners.*/
 .gdrive-welcome-wrapper {
   background-image: url('../images/clouds.png');
   background-repeat: repeat-x;
 }
 
@@ skipping 104 matching lines @@
   margin-bottom: 30px;
 }
 
 .gdrive-welcome.page .gdrive-welcome-text {
   margin-bottom: 24px;
 }
 
 .gdrive-welcome.page .gdrive-welcome-dismiss {
   margin-left: 20px;
 }
+
+body:not([type='full-page']) .gdrive-welcome.page .gdrive-welcome-title {
+  text-align: center;
+}
+
+body:not([type='full-page']) .gdrive-welcome.page .gdrive-welcome-wrapper {
+  background-position: 0 0;
+}
+
+body:not([type='full-page']) .gdrive-welcome.page .gdrive-welcome-icon {
+  height: 200px;
+}
+
+body:not([type='full-page']) .gdrive-welcome.page .gdrive-welcome-message {
+  padding-left: 10%;
+  padding-right: 10%;
+}