[cros] Initialize OOBE in parallel when boot animation is disabled.

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 3caf2fea13d7ed7b6a9ad72cb777cfdea9b51821..975d25dc2fdac78a99f32bc4efe9f87553c0a5ba 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -462,7 +462,8 @@ void Shell::Init() {
   // Initialize Primary RootWindow specific items.
   status_area_widget_ = new internal::StatusAreaWidget();
   status_area_widget_->CreateTrayViews(delegate_.get());
-  status_area_widget_->Show();
+  if (delegate_.get() && delegate_->IsStatusAreaInitiallyVisible())
+    status_area_widget_->Show();
 
   focus_cycler_.reset(new internal::FocusCycler());
   focus_cycler_->AddWidget(status_area_widget_);