[ash-md] Removed unwanted TODO from ShelfWidget::DelegateView::opaque_background_

ash/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/shelf/shelf_widget.h"
 
 #include "ash/animation/animation_change_type.h"
 #include "ash/focus_cycler.h"
 #include "ash/public/cpp/window_properties.h"
 #include "ash/root_window_controller.h"
@@ skipping 48 matching lines @@
   void OnBoundsChanged(const gfx::Rect& old_bounds) override;
 
   // ShelfBackgroundAnimatorObserver:
   void UpdateShelfBackground(SkColor color) override;
 
  private:
   ShelfWidget* shelf_widget_;
   FocusCycler* focus_cycler_;
   // A black background layer that may be visible depending on a
   // ShelfBackgroundAnimator.
-  // TODO(bruthig): Remove opaque_background_ (see https://crbug.com/621551).
   ui::Layer opaque_background_;
   // A black foreground layer which is shown while transitioning between users.
   // Note: Since the back- and foreground layers have different functions they
   // can be used simultaneously - so no repurposing possible.
   ui::Layer opaque_foreground_;
 
   DISALLOW_COPY_AND_ASSIGN(DelegateView);
 };
 
 ShelfWidget::DelegateView::DelegateView(ShelfWidget* shelf_widget)
@@ skipping 264 matching lines @@
   if (shelf_view_)
     shelf_view_->UpdateShelfItemBackground(color);
 }
 
 void ShelfWidget::WillDeleteShelfLayoutManager() {
   shelf_layout_manager_->RemoveObserver(this);
   shelf_layout_manager_ = nullptr;
 }
 
 }  // namespace ash