GTK: More raw struct access removal, this time focusing on GtkDialog.

chrome/browser/ui/gtk/update_recommended_dialog.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 "chrome/browser/ui/gtk/update_recommended_dialog.h"
 
 #include <gtk/gtk.h>
 
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/ui/browser_list.h"
@@ skipping 21 matching lines @@
       NULL);
 
   g_signal_connect(dialog_, "response", G_CALLBACK(OnResponseThunk), this);
 
   // Add the message text.
   std::string text(
       l10n_util::GetStringFUTF8(IDS_UPDATE_RECOMMENDED,
                                 l10n_util::GetStringUTF16(IDS_PRODUCT_NAME)));
   GtkWidget* label = gtk_label_new(text.c_str());
   gtk_util::SetLabelWidth(label, kMessageWidth);
-  gtk_box_pack_start(GTK_BOX(GTK_DIALOG(dialog_)->vbox), label,
-                     FALSE, FALSE, 0);
+
+  GtkWidget* content_area = gtk_dialog_get_content_area(GTK_DIALOG(dialog_));
+  gtk_box_pack_start(GTK_BOX(content_area), label, FALSE, FALSE, 0);
 
   gtk_window_set_resizable(GTK_WINDOW(dialog_), FALSE);
 
   gtk_widget_show_all(dialog_);
 }
 
 UpdateRecommendedDialog::~UpdateRecommendedDialog() {
 }
 
 void UpdateRecommendedDialog::OnResponse(GtkWidget* dialog, int response_id) {
   gtk_widget_destroy(dialog_);
 
   if (response_id == GTK_RESPONSE_ACCEPT) {
     BrowserList::AttemptRestart();
   }
 
   delete this;
 }