Restore to user selected wallpaper after browser crash

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 395d2bf6a3582c00dc5f3b8be6ad74899a6472a1..54c6d3176f74191ffead4c18404b41afd276a28c 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -598,6 +598,8 @@ void Shell::Init() {
 
   // This controller needs to be set before SetupManagedWindowMode.
   desktop_background_controller_.reset(new DesktopBackgroundController);
+  if (delegate_.get())
+    user_wallpaper_delegate_.reset(delegate_->CreateUserWallpaperDelegate());
 
   InitLayoutManagers();
 
@@ -753,8 +755,11 @@ void Shell::InitLayoutManagers() {
   // Ensure launcher is visible.
   launcher_->widget()->Show();
 
-  // Create the desktop background image.
-  desktop_background_controller_->SetDefaultDesktopBackgroundImage();
+  // Create desktop background widget.
+  // TODO(bshe): We should be able to use OnDesktopBackgroundChanged function
+  // here after issue 117244 got fixed.
+  desktop_background_controller_->SetDesktopBackgroundImageMode(
+      GetWallpaper(user_wallpaper_delegate_->GetUserWallpaperIndex()));
 }
 
 void Shell::DisableWorkspaceGridLayout() {