Resize and save custom wallpaper to large and small size

ash/desktop_background/desktop_background_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_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_H_
 #define ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_H_
 
 #include "ash/ash_export.h"
 #include "ash/desktop_background/desktop_background_resources.h"
 #include "ash/wm/window_animations.h"
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
 #include "ui/compositor/layer.h"
 #include "ui/gfx/image/image_skia.h"
 
 typedef unsigned int SkColor;
 
 namespace aura {
 class RootWindow;
 }
 
 namespace ash {
 
+// The width and height of small/large resolution wallpaper. When screen size is
+// smaller than |kSmallWallpaperMaxWidth| and |kSmallWallpaperMaxHeight|, the
+// small resolution wallpaper should be used. Otherwise, uses the large
+// resolution wallpaper.
+ASH_EXPORT extern const int kSmallWallpaperMaxWidth;
+ASH_EXPORT extern const int kSmallWallpaperMaxHeight;
+ASH_EXPORT extern const int kLargeWallpaperMaxWidth;
+ASH_EXPORT extern const int kLargeWallpaperMaxHeight;
+
 class UserWallpaperDelegate {
  public:
   virtual ~UserWallpaperDelegate() {}
 
   // Returns type of window animation that should be used when showin wallpaper.
   virtual ash::WindowVisibilityAnimationType GetAnimationType() = 0;
 
   // Initialize wallpaper.
   virtual void InitializeWallpaper() = 0;
 
@@ skipping 132 matching lines @@
   scoped_refptr<WallpaperOperation> wallpaper_op_;
 
   base::WeakPtrFactory<DesktopBackgroundController> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopBackgroundController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_CONTROLLER_H_