Prefer ScopedNestableTaskAllower over manual save/restore

webkit/tools/test_shell/test_shell_devtools_agent.cc

Index: webkit/tools/test_shell/test_shell_devtools_agent.cc
diff --git a/webkit/tools/test_shell/test_shell_devtools_agent.cc b/webkit/tools/test_shell/test_shell_devtools_agent.cc
index b2e4a953e8a380709c77660f69f2ca8b0e4a4b39..895e36206bc364b3025a8d140683c4663164d551 100644
--- a/webkit/tools/test_shell/test_shell_devtools_agent.cc
+++ b/webkit/tools/test_shell/test_shell_devtools_agent.cc
@@ -29,10 +29,8 @@ class WebKitClientMessageLoopImpl
     message_loop_ = NULL;
   }
   virtual void run() {
-    bool old_state = message_loop_->NestableTasksAllowed();
-    message_loop_->SetNestableTasksAllowed(true);
+    MessageLoop::ScopedNestableTaskAllower allow(message_loop_);
     message_loop_->Run();
-    message_loop_->SetNestableTasksAllowed(old_state);
   }
   virtual void quitNow() {
     message_loop_->QuitNow();