ash: Some code-cleanup in the system-tray code.

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 56a12c3748d09358dfa01caf7c69d5caca84c20d..74ff8fcecb7b259ab0aeb997367fd35c0055e221 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -365,11 +365,7 @@ class ASH_EXPORT Shell {
   // Owned by aura::RootWindow, cached here for type safety.
   internal::RootWindowLayoutManager* root_window_layout_;
 
-  // Status area with clock, Wi-Fi signal, etc.
-  views::Widget* status_widget_;
-
-  // System tray with clock, Wi-Fi signal, etc. (a replacement in progress for
-  // |status_widget_|).
+  // System tray with clock, Wi-Fi signal, etc.
   scoped_ptr<SystemTray> tray_;
 
   // Used by ash/shell.