app_list: Fix possible out of bounds index.

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 385 matching lines @@
   void CalculateNearestTileForVertex(
       const gfx::Point& vertex, Index* nearest_tile, int* d_min);
 
   // Returns the bounds of the tile in which |point| is enclosed if there
   // is a valid item sits on the tile.
   gfx::Rect GetTileBoundsForPoint(const gfx::Point& point, Index* tile_index);
 
   // Gets the bounds of the tile located at |row| and |col| on current page.
   gfx::Rect GetTileBounds(int row, int col) const;
 
-  // Returns true if the slot of |index| is the first empty slot next to the
-  // last item on the last page.
-  bool IsFirstEmptySlot(const Index& index) const;
+  // Returns true if the slot of |index| is the last possible slot to drop
+  // an item, i.e. first empty slot next to the last item on the last page.
+  bool IsLastPossibleDropTarget(const Index& index) const;
 
   // Gets the item view located at |slot| on the current page. If there is
   // no item located at |slot|, returns NULL.
   views::View* GetViewAtSlotOnCurrentPage(int slot);
 
   // Sets state of the view with |target_index| to |is_target_folder| for
   // dropping |drag_view_|.
   void SetAsFolderDroppingTarget(const Index& target_index,
                                  bool is_target_folder);
 
@@ skipping 71 matching lines @@
   // The location of |drag_view_| when the drag started.
   gfx::Point drag_view_start_;
 
   // Page the drag started on.
   int drag_start_page_;
 
 #if defined(OS_WIN)
   // Created when a drag is started (ie: drag exceeds the drag threshold), but
   // not Run() until supplied with a shortcut path.
   scoped_refptr<SynchronousDrag> synchronous_drag_;
+
+  // Whether to use SynchronousDrag to support dropping to task bar etc.
+  bool use_synchronous_drag_;
 #endif
 
   Pointer drag_pointer_;
   Index drop_target_;
   DropAttempt drop_attempt_;
 
   // Timer for re-ordering the |drop_target_| and |drag_view_|.
   base::OneShotTimer<AppsGridView> reorder_timer_;
 
   // Timer for dropping |drag_view_| into the folder containing
@@ skipping 34 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_