Add --use-more-webui runtime flag to toggle WebUI replacements for native dialogs.

chrome/browser/ui/gtk/hung_renderer_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/browser_dialogs.h"
 
 #include <gtk/gtk.h>
 
 #include "base/process_util.h"
 #include "base/utf_string_conversions.h"
@@ skipping 231 matching lines @@
 
   gtk_widget_destroy(GTK_WIDGET(dialog_));
   delete g_instance;
   g_instance = NULL;
 }
 
 }  // namespace
 
 namespace browser {
 
-void ShowHungRendererDialog(TabContents* contents) {
+void ShowNativeHungRendererDialog(TabContents* contents) {
   if (!logging::DialogsAreSuppressed()) {
     if (!g_instance)
       g_instance = new HungRendererDialogGtk();
     g_instance->ShowForTabContents(contents);
   }
 }
 
-void HideHungRendererDialog(TabContents* contents) {
+void HideNativeHungRendererDialog(TabContents* contents) {
   if (!logging::DialogsAreSuppressed() && g_instance)
     g_instance->EndForTabContents(contents);
 }
 
 }  // namespace browser