aura: Uber tray should not show up on start screen in kiosk mode.

ash/shell.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/shell.h"
 
 #include <algorithm>
 
 #include "ash/app_list/app_list.h"
 #include "ash/ash_switches.h"
@@ skipping 225 matching lines @@
         wifi_enabled_(true),
         cellular_enabled_(true),
         bluetooth_enabled_(true),
         volume_(0.5) {
   }
 
   virtual ~DummySystemTrayDelegate() {}
 
  private:
 
+  virtual bool GetTrayVisibilityOnStartup() OVERRIDE { return true; }
+
   // Overridden from SystemTrayDelegate:
   virtual const std::string GetUserDisplayName() const OVERRIDE {
     return "Über tray Über tray Über tray Über tray";
   }
 
   virtual const std::string GetUserEmail() const OVERRIDE {
     return "über@tray";
   }
 
   virtual const SkBitmap& GetUserImage() const OVERRIDE {
@@ skipping 369 matching lines @@
     tray_->AddTrayItem(tray_power);
     tray_->AddTrayItem(tray_network);
     tray_->AddTrayItem(tray_bluetooth);
     tray_->AddTrayItem(tray_ime);
     tray_->AddTrayItem(tray_volume);
     tray_->AddTrayItem(tray_brightness);
     tray_->AddTrayItem(new internal::TraySettings());
     tray_->AddTrayItem(tray_date);
     tray_->AddTrayItem(tray_accessibility);
     tray_->AddTrayItem(tray_caps_lock);
+
+    tray_->SetVisible(tray_delegate_->GetTrayVisibilityOnStartup());
   }
   if (!status_widget_)
     status_widget_ = internal::CreateStatusArea(tray_.get());
 
   // This controller needs to be set before SetupManagedWindowMode.
   desktop_background_controller_.reset(new DesktopBackgroundController);
 
   InitLayoutManagers();
 
   if (!command_line->HasSwitch(switches::kAuraNoShadows)) {
@@ skipping 156 matching lines @@
   // Create the desktop background image.
   desktop_background_controller_->SetDefaultDesktopBackgroundImage();
 }
 
 void Shell::DisableWorkspaceGridLayout() {
   if (workspace_controller_.get())
     workspace_controller_->workspace_manager()->set_grid_size(0);
 }
 
 }  // namespace ash