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

ui/views/controls/separator.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_CONTROLS_SEPARATOR_H_
 #define UI_VIEWS_CONTROLS_SEPARATOR_H_
 
 #include <string>
 
 #include "ui/views/view.h"
@@ skipping 10 matching lines @@
     VERTICAL
   };
 
   // The separator's class name.
   static const char kViewClassName[];
 
   explicit Separator(Orientation orientation);
   virtual ~Separator();
 
   // Overridden from View:
-  virtual gfx::Size GetPreferredSize() OVERRIDE;
+  virtual gfx::Size GetPreferredSize() const OVERRIDE;
   virtual void GetAccessibleState(ui::AXViewState* state) OVERRIDE;
   virtual void Paint(gfx::Canvas* canvas,
                      const views::CullSet& cull_set) OVERRIDE;
   virtual const char* GetClassName() const OVERRIDE;
 
  private:
   const Orientation orientation_;
 
   DISALLOW_COPY_AND_ASSIGN(Separator);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_SEPARATOR_H_