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

ui/app_list/views/contents_switcher_view.cc

 // Copyright 2014 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.
 
 #include "ui/app_list/views/contents_switcher_view.h"
 
 #include "grit/ui_resources.h"
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/views/contents_view.h"
 #include "ui/base/resource/resource_bundle.h"
@@ skipping 24 matching lines @@
 
 void ContentsSwitcherView::AddSwitcherButton(int resource_id, int tag) {
   views::ImageButton* button = new views::ImageButton(this);
   button->SetImage(
       views::CustomButton::STATE_NORMAL,
       ui::ResourceBundle::GetSharedInstance().GetImageSkiaNamed(resource_id));
   button->set_tag(tag);
   buttons_->AddChildView(button);
 }
 
-gfx::Size ContentsSwitcherView::GetPreferredSize() {
+gfx::Size ContentsSwitcherView::GetPreferredSize() const {
   return gfx::Size(buttons_->GetPreferredSize().width(), kPreferredHeight);
 }
 
 void ContentsSwitcherView::Layout() {
   gfx::Rect rect(GetContentsBounds());
 
   // Makes |buttons_| horizontally center and vertically fill.
   gfx::Size buttons_size(buttons_->GetPreferredSize());
   gfx::Rect buttons_bounds(rect.CenterPoint().x() - buttons_size.width() / 2,
                            rect.y(),
                            buttons_size.width(),
                            rect.height());
   buttons_->SetBoundsRect(gfx::IntersectRects(rect, buttons_bounds));
 }
 
 void ContentsSwitcherView::ButtonPressed(views::Button* sender,
                                          const ui::Event& event) {
   contents_view_->SetShowState(
       static_cast<ContentsView::ShowState>(sender->tag()));
 }
 
 }  // namespace app_list