Introduce centered view and bottom view for home card.

ui/app_list/views/tile_item_view.h

 // Copyright 2014 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_TILE_ITEM_VIEW_H_
 #define UI_APP_LIST_VIEWS_TILE_ITEM_VIEW_H_
 
+#include "ui/app_list/app_list_export.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/button/custom_button.h"
 
 namespace views {
 class ImageView;
 class Label;
 }
 
 namespace app_list {
 
 class AppListItem;
 
 // The view for a tile in the app list on the start/search page.
-class TileItemView : public views::CustomButton, public views::ButtonListener {
+class APP_LIST_EXPORT TileItemView : public views::CustomButton,
+                                     public views::ButtonListener {
  public:
   TileItemView();
   virtual ~TileItemView();
 
   void SetAppListItem(AppListItem* item);
 
  private:
   class TileItemBackground;
 
   // Overridden from views::View:
@@ skipping 10 matching lines @@
   views::Label* title_;     // Owned by views hierarchy.
 
   TileItemBackground* background_;
 
   DISALLOW_COPY_AND_ASSIGN(TileItemView);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_TILE_ITEM_VIEW_H_