Implement app list folder management page UI.

ui/app_list/views/contents_view.h

Index: ui/app_list/views/contents_view.h
diff --git a/ui/app_list/views/contents_view.h b/ui/app_list/views/contents_view.h
index 4c2c6fef6a10c7fcc4b1765f3d676625814f2948..170a3bcb3e508f3a05b1203a6dff5464f68d40d0 100644
--- a/ui/app_list/views/contents_view.h
+++ b/ui/app_list/views/contents_view.h
@@ -23,9 +23,11 @@ namespace app_list {
 
 class AppsGridView;
 class ApplicationDragAndDropHost;
+class AppListFolderItem;
 class AppListMainView;
 class AppListModel;
 class AppListViewDelegate;
+class AppsContainerView;
 class PaginationModel;
 
 // A view to manage sub views under the search box (apps grid view + page
@@ -49,6 +51,8 @@ class ContentsView : public views::View {
       ApplicationDragAndDropHost* drag_and_drop_host);
 
   void ShowSearchResults(bool show);
+  void ShowFolderContent(AppListFolderItem* folder);
+  void ShowApps();
 
   void Prerender();
 
@@ -80,7 +84,7 @@ class ContentsView : public views::View {
   ShowState show_state_;
   PaginationModel* pagination_model_;  // Owned by AppListController.
 
-  AppsGridView* apps_grid_view_;  // Owned by the view.
+  AppsContainerView* apps_container_view_; // Owned by the views hierarchy.
 
   scoped_ptr<views::ViewModel> view_model_;
   scoped_ptr<views::BoundsAnimator> bounds_animator_;