Remove the extra separator appears on the right side of the shelf

ash/common/system/chromeos/session/logout_button_tray.cc

Index: ash/common/system/chromeos/session/logout_button_tray.cc
diff --git a/ash/common/system/chromeos/session/logout_button_tray.cc b/ash/common/system/chromeos/session/logout_button_tray.cc
index e3cfc2e3b20c7e86c9077f7856605d5567cce2d9..d7723c425251818c38d4b32a7812388c7beefdf8 100644
--- a/ash/common/system/chromeos/session/logout_button_tray.cc
+++ b/ash/common/system/chromeos/session/logout_button_tray.cc
@@ -116,6 +116,10 @@ LogoutButtonTray::LogoutButtonTray(WmShelf* wm_shelf)
     // crbug.com/623987
     button->AdjustFontSize(2);
     button_ = button;
+
+    // Since |logout_button_tray| has a red background and it is distinguished
+    // by itself, no separator is needed on its right side.
+    set_separator_visibility(false);
   } else {
     button_ = new LogoutButton(this);
   }