views: Add optional overlay image to ImageButton

ui/views/examples/button_example.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_VIEWS_EXAMPLES_BUTTON_EXAMPLE_H_
 #define UI_VIEWS_EXAMPLES_BUTTON_EXAMPLE_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/views/controls/button/text_button.h"
 #include "ui/views/examples/example_base.h"
 
 namespace views {
+
+class ImageButton;
 class View;
 
 namespace examples {
 
 // ButtonExample simply counts the number of clicks.
 class ButtonExample : public ExampleBase, public ButtonListener {
  public:
   ButtonExample();
   virtual ~ButtonExample();
 
   // Overridden from ExampleBase:
   virtual void CreateExampleView(View* container) OVERRIDE;
 
  private:
   // Overridden from ButtonListener:
   virtual void ButtonPressed(Button* sender, const Event& event) OVERRIDE;
 
-  // The only control in this test.
-  TextButton* button_;
+  // Example buttons.
+  TextButton* text_button_;
+  ImageButton* image_button_;
 
   // Values used to modify the look and feel of the button.
   TextButton::TextAlignment alignment_;
   bool use_native_theme_border_;
   const SkBitmap* icon_;
 
-  // The number of times the button is pressed.
+  // The number of times the buttons are pressed.
   int count_;
 
   DISALLOW_COPY_AND_ASSIGN(ButtonExample);
 };
 
 }  // namespace examples
 }  // namespace views
 
 #endif  // UI_VIEWS_EXAMPLES_BUTTON_EXAMPLE_H_