ui::ListModel: Added iteration methods begin() and end().

Range-based for loops can now be used with this class. Updated
app_list::Mixer to use a range-based for loop with its ListModel.

Review URL: https://codereview.chromium.org/904023002

Cr-Commit-Position: refs/heads/master@{#316726}

1 files changed, 10 insertions, 0 deletions

diff --git a/ui/base/models/list_model.h b/ui/base/models/list_model.h
index 6955a8f..e358d84 100644
--- a/ui/base/models/list_model.h
+++ b/ui/base/models/list_model.h
@@ -122,6 +122,16 @@ class ListModel {
         const_cast<const ListModel<ItemType>*>(this)->GetItemAt(index));
   }
 
+  // Iteration interface.
+  typename ScopedVector<ItemType>::iterator begin() { return items_.begin(); }
+  typename ScopedVector<ItemType>::const_iterator begin() const {
+    return items_.begin();
+  }
+  typename ScopedVector<ItemType>::iterator end() { return items_.end(); }
+  typename ScopedVector<ItemType>::const_iterator end() const {
+    return items_.end();
+  }
+
  private:
   ScopedVector<ItemType> items_;
   ObserverList<ListModelObserver> observers_;