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

ui/views/layout/fill_layout.cc

 // 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.
 
 #include "ui/views/layout/fill_layout.h"
 
 #include "base/logging.h"
 
 namespace views {
 
 FillLayout::FillLayout() {}
 
 FillLayout::~FillLayout() {}
 
 void FillLayout::Layout(View* host) {
   if (!host->has_children())
     return;
 
   View* frame_view = host->child_at(0);
   frame_view->SetBoundsRect(host->GetContentsBounds());
 }
 
-gfx::Size FillLayout::GetPreferredSize(View* host) {
+gfx::Size FillLayout::GetPreferredSize(const View* host) const {
   if (!host->has_children())
     return gfx::Size();
   DCHECK_EQ(1, host->child_count());
   gfx::Rect rect(host->child_at(0)->GetPreferredSize());
   rect.Inset(-host->GetInsets());
   return rect.size();
 }
 
-int FillLayout::GetPreferredHeightForWidth(View* host, int width) {
+int FillLayout::GetPreferredHeightForWidth(const View* host, int width) const {
   if (!host->has_children())
     return 0;
   DCHECK_EQ(1, host->child_count());
   const gfx::Insets insets = host->GetInsets();
   return host->child_at(0)->GetHeightForWidth(width - insets.width()) +
       insets.height();
 }
 
 }  // namespace views