Make painting app list items more efficient by caching the labels.

ui/app_list/views/app_list_item_view.h

 // Copyright (c) 2012 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_APP_LIST_ITEM_VIEW_H_
 #define UI_APP_LIST_VIEWS_APP_LIST_ITEM_VIEW_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 10 matching lines @@
 namespace views {
 class ImageView;
 class Label;
 class MenuRunner;
 }
 
 namespace app_list {
 
 class AppListItemModel;
 class AppsGridView;
+class CachedLabel;
 
 class APP_LIST_EXPORT AppListItemView : public views::CustomButton,
                                         public views::ContextMenuController,
                                         public AppListItemModelObserver {
  public:
   // Internal class name.
   static const char kViewClassName[];
 
   AppListItemView(AppsGridView* apps_grid_view, AppListItemModel* model);
   virtual ~AppListItemView();
@@ skipping 47 matching lines @@
   virtual void OnMouseCaptureLost() OVERRIDE;
   virtual bool OnMouseDragged(const ui::MouseEvent& event) OVERRIDE;
 
   // ui::EventHandler overrides:
   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   AppListItemModel* model_;  // Owned by AppListModel::Apps.
 
   AppsGridView* apps_grid_view_;  // Owned by views hierarchy.
   views::ImageView* icon_;  // Owned by views hierarchy.
-  views::Label* title_;  // Owned by views hierarchy.
+  CachedLabel* title_;  // Owned by views hierarchy.
 
   scoped_ptr<views::MenuRunner> context_menu_runner_;
 
   gfx::Size icon_size_;
   gfx::ShadowValues icon_shadows_;
 
   UIState ui_state_;
 
   // True if scroll gestures should contribute to dragging.
   bool touch_dragging_;
 
   // A timer to defer showing drag UI when mouse is pressed.
   base::OneShotTimer<AppListItemView> mouse_drag_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListItemView);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_APP_LIST_ITEM_VIEW_H_