views: Add optional overlay image to ImageButton

ui/views/controls/button/image_button.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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_CONTROLS_BUTTON_IMAGE_BUTTON_H_
 #define UI_VIEWS_CONTROLS_BUTTON_IMAGE_BUTTON_H_
 #pragma once
 
+#include "base/gtest_prod_util.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/views/controls/button/custom_button.h"
 
 namespace views {
 
 // An image button.
 
 // Note that this type of button is not focusable by default and will not be
 // part of the focus chain.  Call set_focusable(true) to make it part of the
 // focus chain.
 
 class VIEWS_EXPORT ImageButton : public CustomButton {
  public:
   explicit ImageButton(ButtonListener* listener);
   virtual ~ImageButton();
 
   // Set the image the button should use for the provided state.
   virtual void SetImage(ButtonState state, const SkBitmap* image);
 
   // Set the background details.
   void SetBackground(SkColor color,
                      const SkBitmap* image,
                      const SkBitmap* mask);
 
+  // Set an |image| to draw on top of the normal / hot / pushed image.
+  // Pass NULL for no image.
+  void SetOverlayImage(const SkBitmap* image);
+
   enum HorizontalAlignment { ALIGN_LEFT = 0,
                              ALIGN_CENTER,
                              ALIGN_RIGHT, };
 
   enum VerticalAlignment { ALIGN_TOP = 0,
                            ALIGN_MIDDLE,
                            ALIGN_BOTTOM };
 
   // Sets how the image is laid out within the button's bounds.
   void SetImageAlignment(HorizontalAlignment h_align,
@@ skipping 13 matching lines @@
   // Returns the image to paint. This is invoked from paint and returns a value
   // from images.
   virtual SkBitmap GetImageToPaint();
 
   // The images used to render the different states of this button.
   SkBitmap images_[BS_COUNT];
 
   // The background image.
   SkBitmap background_image_;
 
+  // Image to draw on top of normal / hot / pushed image.  Usually empty.
+  SkBitmap overlay_image_;
+
  private:
+  FRIEND_TEST_ALL_PREFIXES(ImageButtonTest, Basics);
+
   // Image alignment.
   HorizontalAlignment h_alignment_;
   VerticalAlignment v_alignment_;
   gfx::Size preferred_size_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageButton);
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 //
@@ skipping 37 matching lines @@
   // The parent class's tooltip_text_ is displayed when not toggled, and
   // this one is shown when toggled.
   string16 toggled_tooltip_text_;
 
   DISALLOW_COPY_AND_ASSIGN(ToggleImageButton);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_IMAGE_BUTTON_H_