Add support for using DOM Distiller in incognito.

chrome/browser/dom_distiller/dom_distiller_service_factory.cc

 // Copyright 2013 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_distiller/dom_distiller_service_factory.h"
 
 #include "base/threading/sequenced_worker_pool.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/dom_distiller/content/distiller_page_web_contents.h"
 #include "components/dom_distiller/core/article_entry.h"
 #include "components/dom_distiller/core/distiller.h"
 #include "components/dom_distiller/core/dom_distiller_store.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "components/leveldb_proto/proto_database.h"
 #include "components/leveldb_proto/proto_database_impl.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 67 matching lines @@
           dom_distiller_store.PassAs<DomDistillerStoreInterface>(),
           distiller_factory.Pass(),
           distiller_page_factory.Pass(),
           distilled_page_prefs.Pass());
 
   return service;
 }
 
 content::BrowserContext* DomDistillerServiceFactory::GetBrowserContextToUse(
     content::BrowserContext* context) const {
-  // TODO(cjhopman): Do we want this to be
-  // GetBrowserContextRedirectedInIncognito?
-  return context;
+  // Makes normal profile and off-the-record profile use same service instance.
+  return chrome::GetBrowserContextRedirectedInIncognito(context);
 }
 
 }  // namespace dom_distiller