views: Factor out Listener from Combobox into its own header file.

ui/views/examples/native_theme_button_example.h

 // Copyright (c) 2011 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_VIEWS_EXAMPLES_NATIVE_THEME_BUTTON_EXAMPLE_H_
 #define UI_VIEWS_EXAMPLES_NATIVE_THEME_BUTTON_EXAMPLE_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "ui/gfx/native_theme.h"
 #include "ui/views/examples/example_base.h"
 #include "views/controls/button/custom_button.h"
-#include "views/controls/combobox/combobox.h"
+#include "views/controls/combobox/combobox_listener.h"
 #include "views/native_theme_delegate.h"
 #include "views/native_theme_painter.h"
 
 namespace views {
 class Combobox;
 class NativeThemePainter;
 }
 
 namespace examples {
 
 // A subclass of button to test native theme rendering.
 class ExampleNativeThemeButton : public views::CustomButton,
                                  public views::NativeThemeDelegate,
-                                 public views::Combobox::Listener {
+                                 public views::ComboboxListener {
  public:
   ExampleNativeThemeButton(views::ButtonListener* listener,
                            views::Combobox* cb_part,
                            views::Combobox* cb_state);
   virtual ~ExampleNativeThemeButton();
 
   std::string MessWithState();
 
  private:
-  // Overridden from View:
+  // Overridden from views::View:
   virtual gfx::Size GetPreferredSize() OVERRIDE;
   virtual void OnPaintBackground(gfx::Canvas* canvas)  OVERRIDE;
 
-  // Overridden from views::Combobox::Listener:
+  // Overridden from views::ComboboxListener:
   virtual void ItemChanged(views::Combobox* combo_box,
                            int prev_index,
                            int new_index) OVERRIDE;
 
   // Overridden from views::NativeThemePainter::Delegate:
   virtual gfx::NativeTheme::Part GetThemePart() const OVERRIDE;
   virtual gfx::Rect GetThemePaintRect() const OVERRIDE;
   virtual gfx::NativeTheme::State GetThemeState(
       gfx::NativeTheme::ExtraParams* params) const OVERRIDE;
   virtual const ui::Animation* GetThemeAnimation() const OVERRIDE;
@@ skipping 32 matching lines @@
 
   // The only control in this test.
   ExampleNativeThemeButton* button_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeThemeButtonExample);
 };
 
 }  // namespace examples
 
 #endif  // UI_VIEWS_EXAMPLES_NATIVE_THEME_BUTTON_EXAMPLE_H_