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 5a49becf515d8a57e87f69190ba9b3703d25319c..18029afb703700c1ee90d67bb710bede6273425e 100644
--- a/ash/common/system/chromeos/session/logout_button_tray.cc
+++ b/ash/common/system/chromeos/session/logout_button_tray.cc
@@ -115,6 +115,10 @@ 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);
   }