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

ui/views/window/native_frame_view.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_WINDOW_NATIVE_FRAME_VIEW_H_
 #define UI_VIEWS_WINDOW_NATIVE_FRAME_VIEW_H_
 
 #include "ui/views/window/non_client_view.h"
 
 namespace views {
@@ skipping 10 matching lines @@
   virtual gfx::Rect GetWindowBoundsForClientBounds(
       const gfx::Rect& client_bounds) const OVERRIDE;
   virtual int NonClientHitTest(const gfx::Point& point) OVERRIDE;
   virtual void GetWindowMask(const gfx::Size& size,
                              gfx::Path* window_mask) OVERRIDE;
   virtual void ResetWindowControls() OVERRIDE;
   virtual void UpdateWindowIcon() OVERRIDE;
   virtual void UpdateWindowTitle() OVERRIDE;
 
   // View overrides:
-  virtual gfx::Size GetPreferredSize() OVERRIDE;
-  virtual gfx::Size GetMinimumSize() OVERRIDE;
+  virtual gfx::Size GetPreferredSize() const OVERRIDE;
+  virtual gfx::Size GetMinimumSize() const OVERRIDE;
   virtual gfx::Size GetMaximumSize() OVERRIDE;
 
  private:
   // Our containing frame.
   Widget* frame_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeFrameView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WINDOW_NATIVE_FRAME_VIEW_H_