cros: Add CHECK to ShelfWidget initialization enabling future cleanup.

ash/common/shelf/shelf_widget.cc

 // Copyright 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/shelf/shelf_widget.h"
 
 #include "ash/animation/animation_change_type.h"
 #include "ash/common/focus_cycler.h"
 #include "ash/common/session/session_controller.h"
 #include "ash/common/shelf/app_list_button.h"
@@ skipping 232 matching lines @@
 
   // Ensure the newly created |shelf_| gets current values.
   background_animator_.NotifyObserver(this);
 
   // TODO(jamescook): The IsActiveUserSessionStarted() check may not be needed
   // because the shelf is only created after the first user session is active.
   // The ShelfView seems to always be visible after login. At the lock screen
   // the shelf is hidden because its container is hidden. During auto-hide it is
   // hidden because ShelfWidget is transparent. Some of the ShelfView visibility
   // code could be simplified. http://crbug.com/674773
+  // TODO(jdufualt|jamescook): Remove CHECK and shelf_view_->SetVisible call in
+  // m60 or beyond (see above TODO).
+  CHECK(Shell::Get()->session_controller()->IsActiveUserSessionStarted());
   shelf_view_->SetVisible(
       Shell::Get()->session_controller()->IsActiveUserSessionStarted());
   shelf_layout_manager_->LayoutShelf();
   shelf_layout_manager_->UpdateAutoHideState();
   Show();
 }
 
 bool ShelfWidget::IsShelfVisible() const {
   return shelf_view_ && shelf_view_->visible();
 }
@@ skipping 86 matching lines @@
   if (shelf_view_)
     shelf_view_->UpdateShelfItemBackground(color);
 }
 
 void ShelfWidget::WillDeleteShelfLayoutManager() {
   shelf_layout_manager_->RemoveObserver(this);
   shelf_layout_manager_ = nullptr;
 }
 
 }  // namespace ash