[Reland] cheets: implement cros side of WallpaperManager API.

chrome/browser/chromeos/arc/arc_wallpaper_handler.h

-// Copyright 2016 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 CHROME_BROWSER_CHROMEOS_ARC_ARC_WALLPAPER_HANDLER_H_
-#define CHROME_BROWSER_CHROMEOS_ARC_ARC_WALLPAPER_HANDLER_H_
-
-#include <stdint.h>
-
-#include <memory>
-#include <set>
-#include <vector>
-
-#include "base/macros.h"
-#include "chrome/browser/image_decoder.h"
-#include "components/arc/set_wallpaper_delegate.h"
-
-class SkBitmap;
-
-namespace arc {
-
-// Lives on the UI thread.
-class ArcWallpaperHandler : public SetWallpaperDelegate,
-                            public ImageDecoder::ImageRequest {
- public:
-  ArcWallpaperHandler();
-  ~ArcWallpaperHandler() override;
-
-  // SetWallpaperDelegate implementation.
-  void SetWallpaper(std::vector<uint8_t> jpeg_data) override;
-
-  // ImageDecoder::ImageRequest implementation.
-  void OnImageDecoded(const SkBitmap& bitmap) override;
-  void OnDecodeImageFailed() override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ArcWallpaperHandler);
-};
-
-}  // namespace arc
-
-#endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_WALLPAPER_HANDLER_H_