Reorder browser list on workspace switch

ui/views/widget/desktop_aura/x11_desktop_handler.h

Index: ui/views/widget/desktop_aura/x11_desktop_handler.h
diff --git a/ui/views/widget/desktop_aura/x11_desktop_handler.h b/ui/views/widget/desktop_aura/x11_desktop_handler.h
index 47a1ff1a7ffd2854d5218ac8cd7b3c579c000267..c1e7f99873425bcd2de3321cb3e061116e7d0f3b 100644
--- a/ui/views/widget/desktop_aura/x11_desktop_handler.h
+++ b/ui/views/widget/desktop_aura/x11_desktop_handler.h
@@ -13,12 +13,14 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "base/observer_list.h"
 #include "ui/aura/env_observer.h"
 #include "ui/events/platform/platform_event_dispatcher.h"
 #include "ui/events/platform/x11/x11_event_source.h"
 #include "ui/gfx/x/x11_atom_cache.h"
 #include "ui/gfx/x/x11_types.h"
 #include "ui/views/views_export.h"
+#include "ui/views/widget/desktop_aura/x11_desktop_handler_observer.h"
 
 namespace base {
 template <typename T> struct DefaultSingletonTraits;
@@ -35,6 +37,10 @@ class VIEWS_EXPORT X11DesktopHandler : public ui::PlatformEventDispatcher,
   // Returns the singleton handler.
   static X11DesktopHandler* get();
 
+  // Adds/removes X11DesktopHandlerObservers.
+  void AddObserver(X11DesktopHandlerObserver* observer);
+  void RemoveObserver(X11DesktopHandlerObserver* observer);
+
   // Gets/sets the X11 server time of the most recent mouse click, touch or
   // key press on a Chrome window.
   int wm_user_time_ms() const { return wm_user_time_ms_; }
@@ -105,6 +111,8 @@ class VIEWS_EXPORT X11DesktopHandler : public ui::PlatformEventDispatcher,
 
   bool wm_supports_active_window_;
 
+  base::ObserverList<X11DesktopHandlerObserver> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(X11DesktopHandler);
 };