Allow full-screen mode when not connected, and remember the previous setting.

remoting/webapp/crd/html/window_frame.css

 /* Copyright 2014 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.
  */
 
 .window-body {
   position: relative;
 }
 
 html.apps-v2,
@@ skipping 104 matching lines @@
 /* Remove dark borders for elements that are adjacent an existing border. */
 .window-close::after {
   border-right: none;
 }
 
 .window-controls-stub::after {
   border-bottom: none;
   border-right: none;
 }
 
-/* The Disconnect, full-screen and options buttons are only displayed when
-   connected. */
+/* The Disconnect and options buttons are only displayed when connected. */
 body:not(.connected) .window-disconnect,
-body:not(.connected) .window-fullscreen,
 body:not(.connected) .window-options {
   display: none;
 }
 
 
 /*
  * When in full-screen mode, significant changes are made:
  * - The scroll-bars are removed.
  * - The window controls have a border (so the left-border of the first button
  *   is not needed).
@@ skipping 53 matching lines @@
   box-shadow: 1px 1px 10px rgba(0, 0, 0, 0.5);
 }
 
 .fullscreen .title-bar.opened .window-controls-stub {
   background-color: #a6a6a6;
 }
 
 body.fullscreen .window-fullscreen {
   display: none;
 }