mash: Show status area widget, attempt 2

ash/mus/root_window_controller.h

Index: ash/mus/root_window_controller.h
diff --git a/ash/mus/root_window_controller.h b/ash/mus/root_window_controller.h
index ae1f013a5ced37a998538a297e57a34cc16720c8..de593d3258567a4ec22941b5793a593cd18b6cac 100644
--- a/ash/mus/root_window_controller.h
+++ b/ash/mus/root_window_controller.h
@@ -49,8 +49,6 @@ class RootWindowController : public ShelfLayoutManagerDelegate {
 
   ui::Window* root() { return root_; }
 
-  int window_count() { return window_count_; }
-
   ui::Window* NewTopLevelWindow(
       std::map<std::string, std::vector<uint8_t>>* properties);
 
@@ -85,6 +83,9 @@ class RootWindowController : public ShelfLayoutManagerDelegate {
   // Creates the necessary set of layout managers in the shell windows.
   void CreateLayoutManagers();
 
+  // Creates the status area widget that contains the system tray menu.
+  void CreateStatusArea();
+
   WindowManager* window_manager_;
   ui::Window* root_;
   int window_count_ = 0;