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

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 ca18e32095f42947eb924ba59d348144e19d6869..106d678070144ee754a9e8f5618af1fd503eb7c4 100644
--- a/ash/common/system/chromeos/session/logout_button_tray.cc
+++ b/ash/common/system/chromeos/session/logout_button_tray.cc
@@ -14,6 +14,7 @@
 #include "ash/common/system/tray/tray_constants.h"
 #include "ash/common/system/tray/tray_utils.h"
 #include "ash/common/system/user/login_status.h"
+#include "ash/common/system/view_observer.h"
 #include "ash/common/wm_shell.h"
 #include "base/logging.h"
 #include "grit/ash_resources.h"
@@ -93,14 +94,14 @@ LogoutButton::LogoutButton(views::ButtonListener* listener)
 
 LogoutButton::~LogoutButton() {}
 
-LogoutButtonTray::LogoutButtonTray(WmShelf* wm_shelf)
-    : TrayBackgroundView(wm_shelf),
+LogoutButtonTray::LogoutButtonTray(WmShelf* wm_shelf,
+                                   ViewObserver* view_observer)
+    : TrayBackgroundView(wm_shelf, view_observer),
       button_(NULL),
       login_status_(LoginStatus::NOT_LOGGED_IN),
       show_logout_button_in_tray_(false) {
   button_ = new LogoutButton(this);
   tray_container()->AddChildView(button_);
-  tray_container()->SetBorder(views::Border::NullBorder());
   WmShell::Get()->system_tray_notifier()->AddLogoutButtonObserver(this);
 }
 
@@ -110,7 +111,6 @@ LogoutButtonTray::~LogoutButtonTray() {
 
 void LogoutButtonTray::SetShelfAlignment(ShelfAlignment alignment) {
   TrayBackgroundView::SetShelfAlignment(alignment);
-  tray_container()->SetBorder(views::Border::NullBorder());
 }
 
 base::string16 LogoutButtonTray::GetAccessibleNameForTray() {