Add always-on-top property to app windows

ui/views/widget/desktop_aura/desktop_root_window_host_x11.h

Index: ui/views/widget/desktop_aura/desktop_root_window_host_x11.h
diff --git a/ui/views/widget/desktop_aura/desktop_root_window_host_x11.h b/ui/views/widget/desktop_aura/desktop_root_window_host_x11.h
index 2c3a5267cf38628d24ed17f031064dc64d11bb4a..0e590c6135b9f8aecfdce75b37236b574c393b9a 100644
--- a/ui/views/widget/desktop_aura/desktop_root_window_host_x11.h
+++ b/ui/views/widget/desktop_aura/desktop_root_window_host_x11.h
@@ -106,6 +106,7 @@ class VIEWS_EXPORT DesktopRootWindowHostX11 :
   virtual bool IsMinimized() const OVERRIDE;
   virtual bool HasCapture() const OVERRIDE;
   virtual void SetAlwaysOnTop(bool always_on_top) OVERRIDE;
+  virtual bool IsAlwaysOnTop() const OVERRIDE;
   virtual void SetWindowTitle(const string16& title) OVERRIDE;
   virtual void ClearNativeFocus() OVERRIDE;
   virtual Widget::MoveLoopResult RunMoveLoop(
@@ -231,6 +232,9 @@ private:
   // server and local window_properties_ during app-initiated fullscreen.
   bool is_fullscreen_;
 
+  // True if the window should stay on top of other windows.
+  bool always_on_top_;
+
   // We are owned by the RootWindow, but we have to have a back pointer to it.
   aura::RootWindow* root_window_;