Make notifier settings combobox a real combobox.

ui/base/models/combobox_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_COMBOBOX_MODEL_H_
 #define UI_BASE_MODELS_COMBOBOX_MODEL_H_
 
 #include "base/strings/string16.h"
 #include "ui/base/ui_base_export.h"
 
@@ skipping 18 matching lines @@
   // interaction).
   virtual int GetDefaultIndex() const;
 
   // Returns true if the item at |index| is enabled.
   virtual bool IsItemEnabledAt(int index) const;
 
   // Adds/removes an observer. Override if model supports mutation.
   virtual void AddObserver(ComboboxModelObserver* observer) {}
   virtual void RemoveObserver(ComboboxModelObserver* observer) {}
 
- protected:
   virtual ~ComboboxModel() {}

[sky, 2016/09/01 04:13:03]

Move to top now. In general I would prefer to keep this protected, but I get why
you want it.

[Evan Stade, 2016/09/01 20:08:41]

Done.

 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_MODELS_COMBOBOX_MODEL_H_