Clean up public interface of AttachmentBrokerUnprivileged.

remoting/host/remoting_me2me_host.cc

Index: remoting/host/remoting_me2me_host.cc
diff --git a/remoting/host/remoting_me2me_host.cc b/remoting/host/remoting_me2me_host.cc
index a80ef55b04ccd02ee409911c4d40f500a6f1d17d..9004846aac9a4949d73879419ac0ae4160746a35 100644
--- a/remoting/host/remoting_me2me_host.cc
+++ b/remoting/host/remoting_me2me_host.cc
@@ -461,9 +461,6 @@ class HostProcess : public ConfigWatcher::Delegate,
   // Accessed on the UI thread.
   scoped_ptr<IPC::ChannelProxy> daemon_channel_;
 
-  // AttachmentBroker for |daemon_channel_|.
-  scoped_ptr<IPC::AttachmentBrokerUnprivileged> attachment_broker_;
-
   // Owned as |desktop_environment_factory_|.
   DesktopSessionConnector* desktop_session_connector_ = nullptr;
 #endif  // defined(REMOTING_MULTI_PROCESS)
@@ -545,11 +542,10 @@ bool HostProcess::InitWithCommandLine(const base::CommandLine* cmd_line) {
                                               this,
                                               context_->network_task_runner());
 
-  attachment_broker_ = IPC::AttachmentBrokerUnprivileged::CreateBroker();
-  if (attachment_broker_) {
-    attachment_broker_->DesignateBrokerCommunicationChannel(
-        daemon_channel_.get());
-  }
+  IPC::AttachmentBrokerUnprivileged::CreateBrokerIfNeeded();
+  IPC::AttachmentBroker* broker = IPC::AttachmentBroker::GetGlobal();
+  if (broker && !broker->IsPrivilegedBroker())
+    broker->RegisterBrokerCommunicationChannel(daemon_channel_.get());
 
 #else  // !defined(REMOTING_MULTI_PROCESS)
   if (cmd_line->HasSwitch(kHostConfigSwitchName)) {
@@ -931,7 +927,9 @@ void HostProcess::ShutdownOnUiThread() {
   policy_watcher_.reset();
 
 #if defined(REMOTING_MULTI_PROCESS)
-  attachment_broker_.reset();
+  IPC::AttachmentBroker* broker = IPC::AttachmentBroker::GetGlobal();
+  if (broker && !broker->IsPrivilegedBroker())
+    broker->DeregisterBrokerCommunicationChannel(daemon_channel_.get());
   daemon_channel_.reset();
 #endif  // defined(REMOTING_MULTI_PROCESS)