gtk: Use gtk_dialog_get_content_area() throughout.

chrome/browser/ui/gtk/bookmarks/bookmark_editor_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/gtk/bookmarks/bookmark_editor_gtk.h"
 
 #include <gtk/gtk.h>
 #include <set>
 
 #include "base/basictypes.h"
@@ skipping 325 matching lines @@
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   // |||+---------------------------------------------------------+|||
   // ||+-----------------------------------------------------------+||
   // |+-------------------------------------------------------------+|
   // +---------------------------------------------------------------+
   //
   // * The url and corresponding label are not shown if creating a new folder.
-  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), gtk_util::kContentAreaSpacing);
 
   GtkWidget* vbox = gtk_vbox_new(FALSE, 12);
 
   name_entry_ = gtk_entry_new();
   std::string title;
   GURL url;
   if (details_.type == EditDetails::EXISTING_NODE) {
     title = UTF16ToUTF8(details_.existing_node->GetTitle());
     url = details_.existing_node->url();
@@ skipping 322 matching lines @@
       GTK_TREE_MODEL(tree_store_), &new_item_iter);
   gtk_tree_view_expand_to_path(GTK_TREE_VIEW(tree_view_), path);
 
   // Make the folder name editable.
   gtk_tree_view_set_cursor(GTK_TREE_VIEW(tree_view_), path,
       gtk_tree_view_get_column(GTK_TREE_VIEW(tree_view_), 0),
       TRUE);
 
   gtk_tree_path_free(path);
 }