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

ui/app_list/views/folder_header_view.h

 // Copyright (c) 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_APP_LIST_VIEWS_FOLDER_HEADER_VIEW_H_
 #define UI_APP_LIST_VIEWS_FOLDER_HEADER_VIEW_H_
 
 #include <string>
 
 #include "ui/app_list/app_list_export.h"
@@ skipping 23 matching lines @@
                                          public AppListItemObserver {
  public:
   explicit FolderHeaderView(FolderHeaderViewDelegate* delegate);
   virtual ~FolderHeaderView();
 
   void SetFolderItem(AppListFolderItem* folder_item);
   void UpdateFolderNameVisibility(bool visible);
   void OnFolderItemRemoved();
 
   // Overridden from views::View:
-  virtual gfx::Size GetPreferredSize() OVERRIDE;
+  virtual gfx::Size GetPreferredSize() const OVERRIDE;
 
  private:
   class FolderNameView;
   friend class test::FolderHeaderViewTest;
 
   // Updates UI.
   void Update();
 
   // Updates the accessible name of the folder name control.
   void UpdateFolderNameAccessibleName();
@@ skipping 35 matching lines @@
   FolderHeaderViewDelegate* delegate_;
 
   bool folder_name_visible_;
 
   DISALLOW_COPY_AND_ASSIGN(FolderHeaderView);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_FOLDER_HEADER_VIEW_H_