Prefer ScopedNestableTaskAllower over manual save/restore

chrome/test/base/ui_test_utils.cc

 // Copyright (c) 2012 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/test/base/ui_test_utils.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
@@ skipping 248 matching lines @@
                                    MessageLoop::QuitClosure());
 }
 
 }  // namespace
 
 void RunMessageLoop() {
   MessageLoop* loop = MessageLoop::current();
   MessageLoopForUI* ui_loop =
       content::BrowserThread::CurrentlyOn(content::BrowserThread::UI) ?
           MessageLoopForUI::current() : NULL;
-  bool did_allow_task_nesting = loop->NestableTasksAllowed();
-  loop->SetNestableTasksAllowed(true);
+  MessageLoop::ScopedNestableTaskAllower allow(loop);
   if (ui_loop) {
 #if defined(USE_AURA)
     aura::RootWindow::GetInstance()->Run();
 #elif defined(TOOLKIT_VIEWS)
     views::AcceleratorHandler handler;
     ui_loop->RunWithDispatcher(&handler);
 #elif defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
     ui_loop->RunWithDispatcher(NULL);
 #else
     ui_loop->Run();
 #endif
   } else {
     loop->Run();
   }
-  loop->SetNestableTasksAllowed(did_allow_task_nesting);
 }
 
 void RunAllPendingInMessageLoop() {
   MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
   ui_test_utils::RunMessageLoop();
 }
 
 void RunAllPendingInMessageLoop(content::BrowserThread::ID thread_id) {
   if (content::BrowserThread::CurrentlyOn(thread_id)) {
     RunAllPendingInMessageLoop();
@@ skipping 807 matching lines @@
   return taker.TakeRenderWidgetSnapshot(rwh, page_size, page_size, bitmap);
 }
 
 bool TakeEntirePageSnapshot(RenderViewHost* rvh, SkBitmap* bitmap) {
   DCHECK(bitmap);
   SnapshotTaker taker;
   return taker.TakeEntirePageSnapshot(rvh, bitmap);
 }
 
 }  // namespace ui_test_utils