Refactor the wallpaper encoding to another file/class.

chrome/browser/ui/webui/options2/chromeos/wallpaper_source.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 CHROME_BROWSER_UI_WEBUI_OPTIONS2_CHROMEOS_WALLPAPER_SOURCE_H_
 #define CHROME_BROWSER_UI_WEBUI_OPTIONS2_CHROMEOS_WALLPAPER_SOURCE_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/ui/webui/chrome_url_data_manager.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 namespace chromeos {
+
+class SimplePngEncoder;
+
 namespace options2 {
 
 // A DataSource for chrome://wallpaper/ URL, provides current user's wallpaper.
 class WallpaperImageSource : public ChromeURLDataManager::DataSource {
  public:
   WallpaperImageSource();
 
   // ChromeURLDataManager::DataSource implementation.
   virtual void StartDataRequest(const std::string& path,
                                 bool is_incognito,
                                 int request_id) OVERRIDE;
   virtual std::string GetMimeType(const std::string&) const OVERRIDE;
 
  private:
   class WallpaperEncodingOperation;
 
   virtual ~WallpaperImageSource();
 
   // Get wallpaper for request identified by |request_id| in UI thread
   // and pass it to encoding phase.
   void GetCurrentUserWallpaper(int request_id);
 
   // Callback is called when image is obtained from UI thread to
   // encode and send reply to request identified by |request_id|.
   void ImageAcquired(SkBitmap image, int request_id);
 
   // Cancel current image encoding operation.
   void CancelPendingEncodingOperation();
 
-    // Send image stored in |data| as a reply to request
+  // Callback to call if we cancel the wallpaper encode operation.
+  void CancelCallback(int request_id);
+
+  // Send image stored in |data| as a reply to request
   // identifed by |request_id|.
   void SendCurrentUserWallpaper(int request_id,
                                 scoped_refptr<base::RefCountedBytes> data);
 
-  scoped_refptr<WallpaperEncodingOperation> wallpaper_encoding_op_;
+  scoped_refptr<SimplePngEncoder> png_encoder_;
 
   base::WeakPtrFactory<WallpaperImageSource> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WallpaperImageSource);
 };
 
 }  // namespace options2
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_OPTIONS2_CHROMEOS_WALLPAPER_SOURCE_H_