Views: factor out Combobox background and const-ify style

ui/views/examples/combobox_example.cc

 // 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.
 
 #include "ui/views/examples/combobox_example.h"
 
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/views/controls/combobox/combobox.h"
 #include "ui/views/layout/box_layout.h"
@@ skipping 31 matching lines @@
 void ComboboxExample::CreateExampleView(View* container) {
   combobox_ = new Combobox(&combobox_model_);
   combobox_->set_listener(this);
   combobox_->SetSelectedIndex(3);
 
   disabled_combobox_ = new Combobox(&combobox_model_);
   disabled_combobox_->set_listener(this);
   disabled_combobox_->SetSelectedIndex(4);
   disabled_combobox_->SetEnabled(false);
 
-  action_combobox_ = new Combobox(&combobox_model_);
+  action_combobox_ = new Combobox(&combobox_model_, Combobox::STYLE_ACTION);
   action_combobox_->set_listener(this);
-  action_combobox_->SetStyle(Combobox::STYLE_ACTION);
   // Note: STYLE_ACTION comboboxes always have the first item selected by
   // default.
 
   container->SetLayoutManager(new BoxLayout(
       BoxLayout::kVertical,
       1, 1, 1));
   container->AddChildView(combobox_);
   container->AddChildView(disabled_combobox_);
   container->AddChildView(action_combobox_);
 }
 
 void ComboboxExample::OnPerformAction(Combobox* combobox) {
   if (combobox == combobox_) {
     PrintStatus("Selected: %s", base::UTF16ToUTF8(combobox_model_.GetItemAt(
         combobox->selected_index())).c_str());
   } else if (combobox == action_combobox_) {
     PrintStatus("Action: %s", base::UTF16ToUTF8(combobox_model_.GetItemAt(
         combobox->selected_index())).c_str());
   } else {
     NOTREACHED() << "Surprising combobox.";
   }
 }
 
 }  // namespace examples
 }  // namespace views