Remove scoped_ptr for system tray views

ash/system/tray_update.cc

Index: ash/system/tray_update.cc
diff --git a/ash/system/tray_update.cc b/ash/system/tray_update.cc
index 8d1399591a9bfd768662b64d8a1e63af33522f3c..0c0ee041b33bf4c9a6f077234435b9315081716f 100644
--- a/ash/system/tray_update.cc
+++ b/ash/system/tray_update.cc
@@ -69,12 +69,10 @@ bool TrayUpdate::GetInitialVisibility() {
 views::View* TrayUpdate::CreateDefaultView(user::LoginStatus status) {
   if (!Shell::GetInstance()->tray_delegate()->SystemShouldUpgrade())
     return NULL;
-  default_.reset(new UpdateView);
-  return default_.get();
+  return new UpdateView;
 }
 
 void TrayUpdate::DestroyDefaultView() {
-  default_.reset();
 }
 
 void TrayUpdate::OnUpdateRecommended() {