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

ui/views/controls/button/image_button.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_CONTROLS_BUTTON_IMAGE_BUTTON_H_
 #define UI_VIEWS_CONTROLS_BUTTON_IMAGE_BUTTON_H_
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/base/layout.h"
@@ skipping 51 matching lines @@
   void SetPreferredSize(const gfx::Size& preferred_size) {
     preferred_size_ = preferred_size;
   }
 
   // Whether we should draw our images resources horizontally flipped.
   void SetDrawImageMirrored(bool mirrored) {
     draw_image_mirrored_ = mirrored;
   }
 
   // Overridden from View:
-  virtual gfx::Size GetPreferredSize() OVERRIDE;
+  virtual gfx::Size GetPreferredSize() const OVERRIDE;
   virtual const char* GetClassName() const OVERRIDE;
   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
 
  protected:
   // Overridden from View:
   virtual void OnFocus() OVERRIDE;
   virtual void OnBlur() OVERRIDE;
 
   // Returns the image to paint. This is invoked from paint and returns a value
   // from images.
@@ skipping 79 matching lines @@
   // The parent class's tooltip_text_ is displayed when not toggled, and
   // this one is shown when toggled.
   base::string16 toggled_tooltip_text_;
 
   DISALLOW_COPY_AND_ASSIGN(ToggleImageButton);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_IMAGE_BUTTON_H_