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

ui/views/examples/throbber_example.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/examples/throbber_example.h"
 
 #include "ui/views/controls/throbber.h"
 #include "ui/views/layout/fill_layout.h"
 #include "ui/views/view.h"
 
 namespace views {
 namespace examples {
 
 namespace {
 
 // Time in ms per throbber frame.
 const int kThrobberFrameMs = 60;
 
 class ThrobberView : public View {
  public:
   ThrobberView() {
     throbber_ = new Throbber(kThrobberFrameMs, false);
     AddChildView(throbber_);
     throbber_->SetVisible(true);
     throbber_->Start();
   }
 
-  virtual gfx::Size GetPreferredSize() OVERRIDE {
+  virtual gfx::Size GetPreferredSize() const OVERRIDE {
     return gfx::Size(width(), height());
   }
 
   virtual void Layout() OVERRIDE {
     View* child = child_at(0);
     gfx::Size ps = child->GetPreferredSize();
     child->SetBounds((width() - ps.width()) / 2,
                      (height() - ps.height()) / 2,
                      ps.width(), ps.height());
     SizeToPreferredSize();
@@ skipping 13 matching lines @@
 ThrobberExample::~ThrobberExample() {
 }
 
 void ThrobberExample::CreateExampleView(View* container) {
   container->SetLayoutManager(new FillLayout());
   container->AddChildView(new ThrobberView());
 }
 
 }  // namespace examples
 }  // namespace views