Move all wallpaper file loading and decoding from DesktopBackgroundController to WallpaperManager.

ash/desktop_background/wallpaper_resizer.cc

Index: ash/desktop_background/wallpaper_resizer.cc
diff --git a/ash/desktop_background/wallpaper_resizer.cc b/ash/desktop_background/wallpaper_resizer.cc
index 06d8c97da7d53c54b0e06d40c72c8488314c314c..46497b2c1c84b6b45a7d36c0acbdee4e7dfd540e 100644
--- a/ash/desktop_background/wallpaper_resizer.cc
+++ b/ash/desktop_background/wallpaper_resizer.cc
@@ -93,6 +93,8 @@ void Resize(SkBitmap orig_bitmap,
 
 }  // namespace
 
+const int kInvalidResourceID = -1;
+
 // static
 uint32_t WallpaperResizer::GetImageId(const gfx::ImageSkia& image) {
   const gfx::ImageSkiaRep& image_rep = image.GetRepresentation(1.0f);
@@ -102,9 +104,11 @@ uint32_t WallpaperResizer::GetImageId(const gfx::ImageSkia& image) {
 WallpaperResizer::WallpaperResizer(int image_resource_id,
                                    const gfx::Size& target_size,
                                    WallpaperLayout layout)
-    : image_(*(ui::ResourceBundle::GetSharedInstance().
-          GetImageNamed(image_resource_id).ToImageSkia())),
+    : image_(*(ui::ResourceBundle::GetSharedInstance()
+                   .GetImageNamed(image_resource_id)
+                   .ToImageSkia())),
       original_image_id_(GetImageId(image_)),
+      resource_id_(image_resource_id),
       target_size_(target_size),
       layout_(layout),
       weak_ptr_factory_(this) {
@@ -116,6 +120,7 @@ WallpaperResizer::WallpaperResizer(const gfx::ImageSkia& image,
                                    WallpaperLayout layout)
     : image_(image),
       original_image_id_(GetImageId(image_)),
+      resource_id_(kInvalidResourceID),
       target_size_(target_size),
       layout_(layout),
       weak_ptr_factory_(this) {