Remove use of index in wallpaper picker code and some refactor

chrome/browser/chromeos/login/wallpaper_manager.h

Index: chrome/browser/chromeos/login/wallpaper_manager.h
diff --git a/chrome/browser/chromeos/login/wallpaper_manager.h b/chrome/browser/chromeos/login/wallpaper_manager.h
index 5200f707925f53fb3e923b39b6d072059431c3f7..b21359df80c52570e3d60118d77e100262c4ee24 100644
--- a/chrome/browser/chromeos/login/wallpaper_manager.h
+++ b/chrome/browser/chromeos/login/wallpaper_manager.h
@@ -7,7 +7,7 @@
 
 #include <string>
 
-#include "ash/desktop_background/desktop_background_resources.h"
+#include "ash/desktop_background/desktop_background_controller.h"
 #include "base/file_path.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/weak_ptr.h"
@@ -122,8 +122,8 @@ class WallpaperManager: public system::TimezoneSettings::Observer,
                           User::WallpaperType type,
                           const UserImage& wallpaper);
 
-  // Sets wallpaper to default wallpaper at |index|.
-  void SetDefaultWallpaper(int index);
+  // Sets wallpaper to default wallpaper.
+  void SetDefaultWallpaper();
 
   // Sets one of the default wallpapers for the specified user and saves this
   // settings in local state.
@@ -141,9 +141,6 @@ class WallpaperManager: public system::TimezoneSettings::Observer,
   // Sets |email|'s wallpaper.
   void SetUserWallpaper(const std::string& email);
 
-  // Sets the default wallpaper for the sign-in screen.
-  void SetSigninWallpaper();
-
   // Sets wallpaper to |wallpaper|.
   void SetWallpaperFromImageSkia(const gfx::ImageSkia& wallpaper,
                                  ash::WallpaperLayout layout);
@@ -286,9 +283,6 @@ class WallpaperManager: public system::TimezoneSettings::Observer,
   // The file path of current loaded/loading custom/online wallpaper.
   FilePath current_wallpaper_path_;
 
-  // The index of current loaded/loading default wallpaper.
-  int current_default_wallpaper_index_;
-
   // Loads user wallpaper from its file.
   scoped_refptr<UserImageLoader> wallpaper_loader_;