ash: Add GetItemIndexForType() function to ShelfModel.

ash/shelf/shelf_model.h

 // Copyright 2013 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 ASH_SHELF_SHELF_MODEL_H_
 #define ASH_SHELF_SHELF_MODEL_H_
 
 #include "ash/ash_export.h"
 #include "ash/launcher/launcher_types.h"
 #include "base/basictypes.h"
@@ skipping 29 matching lines @@
   // of the model *after* the item at |index| is removed.
   void Move(int index, int target_index);
 
   // Resets the item at the specified index. The item maintains its existing
   // id and type.
   void Set(int index, const LauncherItem& item);
 
   // Returns the index of the item by id.
   int ItemIndexByID(LauncherID id) const;
 
+  // Returns the |index| of the item matching |type| in |items_|.
+  // Returns -1 if the matching item is not found.
+  // Note: Requires a linear search.
+  int GetItemIndexForType(LauncherItemType type);
+
   // Returns the index of the first panel or the index where the first panel
   // would go if there are no panels.
   int FirstPanelIndex() const;
 
   // Returns the id assigned to the next item added.
   LauncherID next_id() const { return next_id_; }
 
   // Returns a reserved id which will not be used by the |ShelfModel|.
   LauncherID reserve_external_id() { return next_id_++; }
 
@@ skipping 22 matching lines @@
   LauncherItems items_;
   Status status_;
   ObserverList<ShelfModelObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfModel);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_MODEL_H_