Similar as extension, DOM UI needs to be created in its own process....

chrome/browser/dom_ui/dom_ui_factory.cc

 // Copyright (c) 2010 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/dom_ui/dom_ui_factory.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/about_flags.h"
 #include "chrome/browser/dom_ui/bookmarks_ui.h"
 #include "chrome/browser/dom_ui/bug_report_ui.h"
@@ skipping 78 matching lines @@
 // when invoked for a particular tab - see NewDOMUI<ExtensionDOMUI>.
 static DOMUIFactoryFunction GetDOMUIFactoryFunction(Profile* profile,
     const GURL& url) {
   // Currently, any gears: URL means an HTML dialog.
   if (url.SchemeIs(chrome::kGearsScheme))
     return &NewDOMUI<HtmlDialogUI>;
 
   if (url.host() == chrome::kChromeUIDialogHost)
     return &NewDOMUI<ConstrainedHtmlUI>;
 
-  ExtensionService* service = profile->GetExtensionService();
+  ExtensionService* service = profile ? profile->GetExtensionService() : NULL;
   if (service && service->ExtensionBindingsAllowed(url))
     return &NewDOMUI<ExtensionDOMUI>;
 
   // All platform builds of Chrome will need to have a cloud printing
   // dialog as backup.  It's just that on Chrome OS, it's the only
   // print dialog.
   if (url.host() == chrome::kCloudPrintResourcesHost)
     return &NewDOMUI<ExternalHtmlDialogUI>;
 
   // This will get called a lot to check all URLs, so do a quick check of other
@@ skipping 219 matching lines @@
   if (page_url.host() == chrome::kChromeUIPluginsHost)
     return PluginsUI::GetFaviconResourceBytes();
 
 #if defined(ENABLE_REMOTING)
   if (page_url.host() == chrome::kChromeUIRemotingHost)
     return RemotingUI::GetFaviconResourceBytes();
 #endif
 
   return NULL;
 }