Convert Pass()→std::move() for iOS build.

ios/chrome/browser/bookmarks/bookmark_model_factory.cc

 // Copyright 2015 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 "ios/chrome/browser/bookmarks/bookmark_model_factory.h"
 
+#include <utility>
+
 #include "base/memory/singleton.h"
 #include "base/prefs/pref_service.h"
 #include "components/bookmarks/browser/bookmark_model.h"
 #include "components/bookmarks/browser/bookmark_utils.h"
 #include "components/bookmarks/browser/startup_task_runner_service.h"
 #include "components/keyed_service/ios/browser_state_dependency_manager.h"
 #include "components/undo/bookmark_undo_service.h"
 #include "ios/chrome/browser/bookmarks/bookmark_client_factory.h"
 #include "ios/chrome/browser/bookmarks/bookmark_client_impl.h"
 #include "ios/chrome/browser/bookmarks/startup_task_runner_service_factory.h"
@@ skipping 51 matching lines @@
       new bookmarks::BookmarkModel(bookmark_client));
   bookmark_model->Load(
       browser_state->GetPrefs(),
       browser_state->GetPrefs()->GetString(prefs::kAcceptLanguages),
       browser_state->GetStatePath(),
       ios::StartupTaskRunnerServiceFactory::GetForBrowserState(browser_state)
           ->GetBookmarkTaskRunner(),
       web::WebThread::GetTaskRunnerForThread(web::WebThread::UI));
   ios::BookmarkUndoServiceFactory::GetForBrowserState(browser_state)
       ->Start(bookmark_model.get());
-  return bookmark_model.Pass();
+  return std::move(bookmark_model);
 }
 
 web::BrowserState* BookmarkModelFactory::GetBrowserStateToUse(
     web::BrowserState* context) const {
   return GetBrowserStateRedirectedInIncognito(context);
 }
 
 bool BookmarkModelFactory::ServiceIsNULLWhileTesting() const {
   return true;
 }
 
 }  // namespace ios