Reset the app list when it is shown on Windows and Linux.

ui/app_list/views/apps_container_view.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_APP_LIST_VIEWS_APPS_CONTAINER_VIEW_H_
 #define UI_APP_LIST_VIEWS_APPS_CONTAINER_VIEW_H_
 
 #include "ui/app_list/app_list_folder_item.h"
 #include "ui/app_list/views/top_icon_animation_view.h"
 #include "ui/views/view.h"
 
 namespace content {
 class WebContents;
 }
 
 namespace app_list {
 
 class AppsGridView;
 class ApplicationDragAndDropHost;
 class AppListFolderItem;
 class AppListFolderView;
+class AppListItemView;
 class AppListMainView;
 class AppListModel;
 class ContentsView;
 class FolderBackgroundView;
 class PaginationModel;
 
 // AppsContainerView contains a root level AppsGridView to render the root level
 // app items, and a AppListFolderView to render the app items inside the
 // active folder. Only one if them is visible to user at any time.
 class AppsContainerView : public views::View,
                           public TopIconAnimationObserver {
  public:
   AppsContainerView(AppListMainView* app_list_main_view,
                     PaginationModel* pagination_model,
                     AppListModel* model,
                     content::WebContents* start_page_contents);
   virtual ~AppsContainerView();
 
   // Shows the active folder content specified by |folder_item|.
   void ShowActiveFolder(AppListFolderItem* folder_item);
 
   // Shows the root level apps list. This is called when UI navigate back from
   // a folder view with |folder_item|. If |folder_item| is NULL skips animation.
   void ShowApps(AppListFolderItem* folder_item);
 
+  void ResetForShow();
+
   // Sets |drag_and_drop_host_| for the current app list in both
   // app_list_folder_view_ and root level apps_grid_view_.
   void SetDragAndDropHostOfCurrentAppList(
       ApplicationDragAndDropHost* drag_and_drop_host);
 
   // Transits the UI from folder view to root lelve apps grid view when
   // re-parenting a child item of |folder_item|.
   void ReparentFolderItemTransit(AppListFolderItem* folder_item);
 
   // views::View overrides:
@@ skipping 31 matching lines @@
       AppListFolderItem* active_folder, bool open_folder);
 
   void PrepareToShowApps(AppListFolderItem* folder_item);
 
   AppListModel* model_;
   AppsGridView* apps_grid_view_;  // Owned by views hierarchy.
   AppListFolderView* app_list_folder_view_;  // Owned by views hierarchy.
   FolderBackgroundView* folder_background_view_;  // Owned by views hierarchy.
   ShowState show_state_;
 
+  // The currently active folder view, if any.
+  AppListItemView* activated_folder_view_;

[tapted, 2014/03/27 11:04:52]

This raw pointer scares me a little - AppListItemViews have a habit of getting
deleted at awkward times.

[calamity, 2014/03/28 03:43:27]

Removed.

+
   // The transitional views for animating the top items in folder
   // when opening or closing a folder.
   std::vector<views::View*> top_icon_views_;
 
   size_t top_icon_animation_pending_count_;
 
   DISALLOW_COPY_AND_ASSIGN(AppsContainerView);
 };
 
 }  // namespace app_list
 
 
 #endif  // UI_APP_LIST_VIEWS_APPS_CONTAINER_VIEW_H_