mash: Migrate wallpaper controllers to ash/common.

ash/common/wallpaper/wallpaper_controller.h

 // 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.
 
-#ifndef ASH_WALLPAPER_WALLPAPER_CONTROLLER_H_
-#define ASH_WALLPAPER_WALLPAPER_CONTROLLER_H_
+#ifndef ASH_COMMON_WALLPAPER_WALLPAPER_CONTROLLER_H_
+#define ASH_COMMON_WALLPAPER_WALLPAPER_CONTROLLER_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/common/shell_observer.h"
 #include "ash/common/wm_display_observer.h"
+#include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/timer/timer.h"
 #include "components/wallpaper/wallpaper_layout.h"
 #include "ui/gfx/image/image_skia.h"
 
 namespace base {
-class SequencedWorkerPool;
+class TaskRunner;
 }
 
 namespace wallpaper {
 class WallpaperResizer;
 }
 
 namespace ash {
 
 class WallpaperControllerObserver;
 
 // Controls the desktop background wallpaper.
 class ASH_EXPORT WallpaperController : public WmDisplayObserver,
                                        public ShellObserver {
  public:
   enum WallpaperMode { WALLPAPER_NONE, WALLPAPER_IMAGE };
 
-  explicit WallpaperController(base::SequencedWorkerPool* blocking_pool);
+  explicit WallpaperController(
+      const scoped_refptr<base::TaskRunner>& task_runner);
   ~WallpaperController() override;
 
   // Add/Remove observers.
   void AddObserver(WallpaperControllerObserver* observer);
   void RemoveObserver(WallpaperControllerObserver* observer);
 
   // Provides current image on the wallpaper, or empty gfx::ImageSkia if there
   // is no image, e.g. wallpaper is none.
   gfx::ImageSkia GetWallpaper() const;
 
@@ skipping 70 matching lines @@
   base::ObserverList<WallpaperControllerObserver> observers_;
 
   std::unique_ptr<wallpaper::WallpaperResizer> current_wallpaper_;
 
   gfx::Size current_max_display_size_;
 
   base::OneShotTimer timer_;
 
   int wallpaper_reload_delay_;
 
-  base::SequencedWorkerPool* blocking_pool_;
+  scoped_refptr<base::TaskRunner> task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(WallpaperController);
 };
 
 }  // namespace ash
 
-#endif  // ASH_WALLPAPER_WALLPAPER_CONTROLLER_H_
+#endif  // ASH_COMMON_WALLPAPER_WALLPAPER_CONTROLLER_H_