Use app list item shadow for app list folders.

ui/app_list/app_list_item.h

Index: ui/app_list/app_list_item.h
diff --git a/ui/app_list/app_list_item.h b/ui/app_list/app_list_item.h
index ab5632fef2fdc0b9d271dcd87426edb9cd36b53a..fafa90c9d55cdc44f4213bf00e7aae75041531d0 100644
--- a/ui/app_list/app_list_item.h
+++ b/ui/app_list/app_list_item.h
@@ -33,9 +33,8 @@ class APP_LIST_EXPORT AppListItem {
   explicit AppListItem(const std::string& id);
   virtual ~AppListItem();
 
-  void SetIcon(const gfx::ImageSkia& icon, bool has_shadow);
+  void SetIcon(const gfx::ImageSkia& icon);
   const gfx::ImageSkia& icon() const { return icon_; }
-  bool has_shadow() const { return has_shadow_; }
 
   const std::string& GetDisplayName() const {
     return short_name_.empty() ? name_ : short_name_;
@@ -121,7 +120,6 @@ class APP_LIST_EXPORT AppListItem {
   std::string folder_id_;  // Id of containing folder; empty if top level item.
   syncer::StringOrdinal position_;
   gfx::ImageSkia icon_;
-  bool has_shadow_;
 
   // The full name of an item. Used for display if |short_name_| is empty.
   std::string name_;