gtk: Use gtk_dialog_get_content_area() throughout.

chrome/browser/ui/input_window_dialog_gtk.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/input_window_dialog.h"
 
 #include <gtk/gtk.h>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
@@ skipping 42 matching lines @@
                   parent,
                   GTK_DIALOG_MODAL,
                   GTK_STOCK_CANCEL, GTK_RESPONSE_REJECT,
                   GTK_STOCK_OK, GTK_RESPONSE_ACCEPT,
                   NULL)),
       delegate_(delegate) {
   gtk_dialog_set_default_response(GTK_DIALOG(dialog_), GTK_RESPONSE_ACCEPT);
   gtk_dialog_set_has_separator(GTK_DIALOG(dialog_), FALSE);
   gtk_window_set_resizable(GTK_WINDOW(dialog_), FALSE);
 
-  GtkWidget* content_area = GTK_DIALOG(dialog_)->vbox;
+  GtkWidget* content_area = gtk_dialog_get_content_area(GTK_DIALOG(dialog_));
   gtk_box_set_spacing(GTK_BOX(content_area), 18);
 
   GtkWidget* hbox = gtk_hbox_new(FALSE, 6);
   GtkWidget* label_widget = gtk_label_new(label.c_str());
   gtk_box_pack_start(GTK_BOX(hbox), label_widget, FALSE, FALSE, 0);
 
   input_ = gtk_entry_new();
   gtk_entry_set_text(GTK_ENTRY(input_), contents.c_str());
   g_signal_connect(input_, "changed",
                    G_CALLBACK(OnEntryChangedThunk), this);
@@ skipping 63 matching lines @@
                                              const string16& window_title,
                                              const string16& label,
                                              const string16& contents,
                                              Delegate* delegate) {
   return new InputWindowDialogGtk(parent,
                                   UTF16ToUTF8(window_title),
                                   UTF16ToUTF8(label),
                                   UTF16ToUTF8(contents),
                                   delegate);
 }