views: Make view::Views::GetPreferredSize() const.

ui/message_center/views/padded_button.h

 // Copyright 2013 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_MESSAGE_CENTER_VIEWS_PADDED_BUTTON_H_
 #define UI_MESSAGE_CENTER_VIEWS_PADDED_BUTTON_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/views/controls/button/image_button.h"
 
 namespace message_center {
 
 // PaddedButtons are ImageButtons whose image can be padded within the button.
 // This allows the creation of buttons like the notification close and expand
 // buttons whose clickable areas extends beyond their image areas
 // (<http://crbug.com/168822>) without the need to create and maintain
 // corresponding resource images with alpha padding. In the future, this class
 // will also allow for buttons whose touch areas extend beyond their clickable
 // area (<http://crbug.com/168856>).
 class PaddedButton : public views::ImageButton {
  public:
   PaddedButton(views::ButtonListener* listener);
   virtual ~PaddedButton();
 
   // Overridden from views::ImageButton:
-  virtual gfx::Size GetPreferredSize() OVERRIDE;
+  virtual gfx::Size GetPreferredSize() const OVERRIDE;
   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
   virtual void OnFocus() OVERRIDE;
 
   // The SetPadding() method also sets the button's image alignment (positive
   // values yield left/top alignments, negative values yield right/bottom ones,
   // and zero values center/middle ones). ImageButton::SetImageAlignment() calls
   // will not affect PaddedButton image alignments.
   void SetPadding(int horizontal_padding, int vertical_padding);
 
   void SetNormalImage(int resource_id);
   void SetHoveredImage(int resource_id);
   void SetPressedImage(int resource_id);
 
  protected:
   gfx::Point ComputePaddedImagePaintPosition(const gfx::ImageSkia& image);
 
  private:
   gfx::Insets padding_;
 
   DISALLOW_COPY_AND_ASSIGN(PaddedButton);
 };
 
 }  // namespace message_center
 
 #endif  // UI_MESSAGE_CENTER_VIEWS_PADDED_BUTTON_H_