Make an AddAll in ListModel.

ui/base/models/list_model.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_BASE_MODELS_LIST_MODEL_H_
 #define UI_BASE_MODELS_LIST_MODEL_H_
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 16 matching lines @@
     DCHECK_LE(index, item_count());
     items_.insert(items_.begin() + index, item);
     NotifyItemsAdded(index, 1);
   }
 
   // Convenience function to append an item to the model.
   void Add(ItemType* item) {
     AddAt(item_count(), item);
   }
 
+  // Add a vector of items to the end of the model. This triggers one
+  // notification after adding all items. No notification is sent if |new_items|
+  // is empty.
+  void AddAll(ScopedVector<ItemType> new_items) {
+    if (new_items.empty())
+      return;
+
+    const size_t count = item_count();
+    items_.insert(items_.end(), new_items.begin(), new_items.end());
+    new_items.weak_clear();
+    NotifyItemsAdded(count, items_.size() - count);
+  }
+
   // Removes an item at given |index| from the model. Note the removed item
   // is NOT deleted and it's up to the caller to delete it.
   ItemType* RemoveAt(size_t index) {
     DCHECK_LT(index, item_count());
     ItemType* item = items_[index];
     items_.weak_erase(items_.begin() + index);
     NotifyItemsRemoved(index, 1);
     return item;
   }
 
@@ skipping 76 matching lines @@
  private:
   ScopedVector<ItemType> items_;
   ObserverList<ListModelObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ListModel<ItemType>);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_MODELS_LIST_MODEL_H_