Remove TileItemBackground from experimental app list.

ui/app_list/views/tile_item_view.h

Index: ui/app_list/views/tile_item_view.h
diff --git a/ui/app_list/views/tile_item_view.h b/ui/app_list/views/tile_item_view.h
index 2f6cefdf732e13405753c7de143fde62aa4a6d3e..baf61aaedd96ead4deb1d736cc6ab141859e87c7 100644
--- a/ui/app_list/views/tile_item_view.h
+++ b/ui/app_list/views/tile_item_view.h
@@ -30,8 +30,6 @@ class APP_LIST_EXPORT TileItemView : public views::CustomButton,
   void SetSearchResult(SearchResult* item);
 
  private:
-  class TileItemBackground;
-
   // Overridden from views::View:
   virtual gfx::Size GetPreferredSize() const OVERRIDE;
 
@@ -49,8 +47,6 @@ class APP_LIST_EXPORT TileItemView : public views::CustomButton,
   views::ImageView* icon_;  // Owned by views hierarchy.
   views::Label* title_;     // Owned by views hierarchy.
 
-  TileItemBackground* background_;
-
   DISALLOW_COPY_AND_ASSIGN(TileItemView);
 };