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

ash/mus/bridge/wm_shelf_mus.h

Index: ash/mus/bridge/wm_shelf_mus.h
diff --git a/ash/mus/bridge/wm_shelf_mus.h b/ash/mus/bridge/wm_shelf_mus.h
index d670d18b729a0a486155aab9696838e1fbd99340..ada6a90ef5f92dcd1cc94b3480becef8ecda3c07 100644
--- a/ash/mus/bridge/wm_shelf_mus.h
+++ b/ash/mus/bridge/wm_shelf_mus.h
@@ -47,6 +47,7 @@ class WmShelfMus : public WmShelf {
   bool ProcessGestureEvent(const ui::GestureEvent& event) override;
   void AddObserver(WmShelfObserver* observer) override;
   void RemoveObserver(WmShelfObserver* observer) override;
+  StatusAreaWidget* GetStatusAreaWidget() override;
   void SetKeyboardBoundsForTesting(const gfx::Rect& bounds) override;
   ShelfLockingManager* GetShelfLockingManagerForTesting() override;
   ShelfView* GetShelfViewForTesting() override;