Refactor app list event handling and prerendering.

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 99 matching lines @@
   void UpdateDrag(Pointer pointer, const gfx::Point& point);
   void EndDrag(bool cancel);
   bool IsDraggedView(const views::View* view) const;
   void ClearDragState();
   void SetDragViewVisible(bool visible);
 
   // Set the drag and drop host for application links.
   void SetDragAndDropHostOfCurrentAppList(
       ApplicationDragAndDropHost* drag_and_drop_host);
 
-  // Prerenders the icons on and around |page_index|.
-  void Prerender(int page_index);
+  // Prerenders the icons on and around the currently selected page.
+  void Prerender();
 
   // Return true if the |bounds_animator_| is animating |view|.
   bool IsAnimatingView(views::View* view);
 
   bool has_dragged_view() const { return drag_view_ != NULL; }
   bool dragging() const { return drag_pointer_ != NONE; }
 
   // Gets the PaginationModel used for the grid view.
   PaginationModel* pagination_model() { return &pagination_model_; }
 
@@ skipping 414 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_