Code:  void WallpaperManager::StartLoadAndSetDefaultWallpaper(
     const base::FilePath& path,
     const wallpaper::WallpaperLayout layout,
     MovableOnDestroyCallbackHolder on_finish,
     std::unique_ptr<user_manager::UserImage>* result_out) {
   user_image_loader::StartWithFilePath(
       task_runner_, path, ImageDecoder::ROBUST_JPEG_CODEC,
       0,  // Do not crop.
       base::Bind(&WallpaperManager::OnDefaultWallpaperDecoded,
                 weak_factory_.GetWeakPtr(), path, layout,
                  base::Unretained(result_out),
                  base::Passed(std::move(on_finish))));
 }

Commit Message: [reland] Do not set default wallpaper unless it should do so.

TBR=bshe@chromium.org, alemate@chromium.org

Bug: 751382
Change-Id: Id0793dfe467f737526a95b1e66ed01fbb8860bda
Reviewed-on: https://chromium-review.googlesource.com/619754
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Reviewed-by: Biao She <bshe@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#498325}
Reviewed-on: https://chromium-review.googlesource.com/646430
Cr-Commit-Position: refs/heads/master@{#498982}
CWE ID: CWE-200
 void WallpaperManager::StartLoadAndSetDefaultWallpaper(
     const base::FilePath& path,
     const wallpaper::WallpaperLayout layout,
    bool update_wallpaper,
     MovableOnDestroyCallbackHolder on_finish,
     std::unique_ptr<user_manager::UserImage>* result_out) {
   user_image_loader::StartWithFilePath(
       task_runner_, path, ImageDecoder::ROBUST_JPEG_CODEC,
       0,  // Do not crop.
       base::Bind(&WallpaperManager::OnDefaultWallpaperDecoded,
                 weak_factory_.GetWeakPtr(), path, layout, update_wallpaper,
                  base::Unretained(result_out),
                  base::Passed(std::move(on_finish))));
 }
