[Chrome OS MD] Draw a 1px separator between 2 tray items

ash/common/system/status_area_widget.h

Index: ash/common/system/status_area_widget.h
diff --git a/ash/common/system/status_area_widget.h b/ash/common/system/status_area_widget.h
index 9ee9143f9ce1fdb6a16801891a727810208bba0b..a829c9fd8fad051e7d9aa9b54b5a3db1437a05ca 100644
--- a/ash/common/system/status_area_widget.h
+++ b/ash/common/system/status_area_widget.h
@@ -17,6 +17,7 @@ class OverviewButtonTray;
 class ShellDelegate;
 class StatusAreaWidgetDelegate;
 class SystemTray;
+class TrayBackgroundView;
 class WebNotificationTray;
 class WmShelf;
 class WmWindow;
@@ -48,6 +49,12 @@ class ASH_EXPORT StatusAreaWidget : public views::Widget,
   // notification tray.
   void UpdateAfterLoginStatusChange(LoginStatus login_status);
 
+  // Based on visibility of |tray| and a tray item on its right, sets |tray|'s
+  // separator visibility either to true or false. Note that no leading
+  // separator is required before the logout_button_tray because that
+  // button's red background is distinctive on its own.
+  void OnTrayVisibilityChanged(TrayBackgroundView* tray);
+
   StatusAreaWidgetDelegate* status_area_widget_delegate() {
     return status_area_widget_delegate_;
   }
@@ -91,6 +98,10 @@ class ASH_EXPORT StatusAreaWidget : public views::Widget,
   void AddPaletteTray();
   void AddVirtualKeyboardTray();
   void AddImeMenuTray();
+
+  // Checks if |tray| is the next visible tray to the left of
+  // |logout_button_tray_|. Returns true if both are visible, false otherwise.
+  bool IsNextVisibleTrayToLogout(TrayBackgroundView* tray) const;
 #endif
   void AddOverviewButtonTray();