App Launcher: Preload the correct number of icons (don't assume 4x4).

ui/app_list/views/apps_grid_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_APPS_GRID_VIEW_H_
 #define UI_APP_LIST_VIEWS_APPS_GRID_VIEW_H_
 
 #include <set>
 #include <string>
 
@@ skipping 62 matching lines @@
   // view, which usually is the hosting AppListView. |pagination_model| is
   // the paging info shared within the launcher UI.
   AppsGridView(AppsGridViewDelegate* delegate,
                PaginationModel* pagination_model);
   virtual ~AppsGridView();
 
   // Sets fixed layout parameters. After setting this, CalculateLayout below
   // is no longer called to dynamically choosing those layout params.
   void SetLayout(int icon_size, int cols, int rows_per_page);
 
-  int cols() { return cols_; }
-  int rows_per_page() { return rows_per_page_; }
+  int cols() const { return cols_; }
+  int rows_per_page() const { return rows_per_page_; }
 
   // This resets the grid view to a fresh state for showing the app list.
   void ResetForShowApps();
 
   // Sets |model| to use. Note this does not take ownership of |model|.
   void SetModel(AppListModel* model);
 
   // Sets the |item_list| to render. Note this does not take ownership of
   // |item_list|.
   void SetItemList(AppListItemList* item_list);
@@ skipping 452 matching lines @@
 
   // True if the drag_view_ item is a folder item being dragged for reparenting.
   bool dragging_for_reparent_item_;
 
   DISALLOW_COPY_AND_ASSIGN(AppsGridView);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_APPS_GRID_VIEW_H_