Fix Chrome crashes on calling OnTrayVisibilityChange

ash/common/system/status_area_widget.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/common/system/status_area_widget.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/system/overview/overview_button_tray.h"
 #include "ash/common/system/status_area_widget_delegate.h"
@@ skipping 59 matching lines @@
   AddLogoutButtonTray();
 #endif
 
   SystemTrayDelegate* delegate = WmShell::Get()->system_tray_delegate();
   DCHECK(delegate);
   // Initialize after all trays have been created.
   system_tray_->InitializeTrayItems(delegate, web_notification_tray_);
   web_notification_tray_->Initialize();
 #if defined(OS_CHROMEOS)
   logout_button_tray_->Initialize();
+  if (palette_tray_)
+    palette_tray_->Initialize();
   virtual_keyboard_tray_->Initialize();
   ime_menu_tray_->Initialize();
 #endif
   overview_button_tray_->Initialize();
   SetShelfAlignment(system_tray_->shelf_alignment());
   UpdateAfterLoginStatusChange(delegate->GetUserLoginStatus());
 }
 
 void StatusAreaWidget::Shutdown() {
   system_tray_->Shutdown();
@@ skipping 207 matching lines @@
   return false;
 }
 #endif
 
 void StatusAreaWidget::AddOverviewButtonTray() {
   overview_button_tray_ = new OverviewButtonTray(wm_shelf_);
   status_area_widget_delegate_->AddTray(overview_button_tray_);
 }
 
 }  // namespace ash