Clean up public interface of AttachmentBrokerUnprivileged.

components/nacl/loader/nacl_listener.cc

Index: components/nacl/loader/nacl_listener.cc
diff --git a/components/nacl/loader/nacl_listener.cc b/components/nacl/loader/nacl_listener.cc
index fae25366e0d89450600f9cefa15b2f917783f709..01c8c24d1f5984366ac44569a160b7238c89ea00 100644
--- a/components/nacl/loader/nacl_listener.cc
+++ b/components/nacl/loader/nacl_listener.cc
@@ -196,8 +196,7 @@ NaClListener::NaClListener()
 #endif
       main_loop_(NULL),
       is_started_(false) {
-  attachment_broker_.reset(
-      IPC::AttachmentBrokerUnprivileged::CreateBroker().release());
+  IPC::AttachmentBrokerUnprivileged::CreateBrokerIfNeeded();
   io_thread_.StartWithOptions(
       base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
   DCHECK(g_listener == NULL);
@@ -258,8 +257,9 @@ void NaClListener::Listen() {
   filter_ = channel_->CreateSyncMessageFilter();
   channel_->AddFilter(new FileTokenMessageFilter());
   channel_->Init(channel_name, IPC::Channel::MODE_CLIENT, true);
-  if (attachment_broker_.get())
-    attachment_broker_->DesignateBrokerCommunicationChannel(channel_.get());
+  IPC::AttachmentBroker* global = IPC::AttachmentBroker::GetGlobal();
+  if (global && !global->IsPrivilegedBroker())
+    global->RegisterBrokerCommunicationChannel(channel_.get());
   main_loop_ = base::MessageLoop::current();
   main_loop_->Run();
 }