X11: Handle change notify for _NET_WORKAREA

ui/views/widget/desktop_aura/desktop_screen_x11.h

 // Copyright (c) 2013 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.
 
 #ifndef UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_
 
 #include <stdint.h>
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/timer/timer.h"
 #include "ui/events/platform/platform_event_dispatcher.h"
 #include "ui/gfx/display_change_notifier.h"
 #include "ui/gfx/screen.h"
+#include "ui/gfx/x/x11_atom_cache.h"
 #include "ui/views/views_export.h"
 
 namespace gfx {
 class Display;
 }
 
 typedef unsigned long XID;
 typedef XID Window;
 typedef struct _XDisplay Display;
 
@@ skipping 60 matching lines @@
 
   // The display objects we present to chrome.
   std::vector<gfx::Display> displays_;
 
   // The timer to delay configuring outputs. See also the comments in
   // Dispatch().
   std::unique_ptr<base::OneShotTimer> configure_timer_;
 
   gfx::DisplayChangeNotifier change_notifier_;
 
+  ui::X11AtomCache atom_cache_;
+
   DISALLOW_COPY_AND_ASSIGN(DesktopScreenX11);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_